Fix spacing around periods (mdn#20313)

files/en-us/learn/css/css_layout/positioning/index.md

@@ -188,7 +188,7 @@ span {
 
 {{ EmbedLiveSample('Setting_position_absolute', '100%', 450) }}
 
-First of all, note that the gap where the positioned element should be in the document flow is no longer there — the first and third elements have closed together like it no longer exists! Well, in a way, this is true. An absolutely positioned element no longer exists in the normal document flow. Instead, it sits on its own layer separate from everything else. This is very useful: it means that we can create isolated UI features that don't interfere with the layout of other elements on the page.  For example, popup information boxes, control menus, rollover panels, UI features that can be dragged and dropped anywhere on the page, and so on.
+First of all, note that the gap where the positioned element should be in the document flow is no longer there — the first and third elements have closed together like it no longer exists! Well, in a way, this is true. An absolutely positioned element no longer exists in the normal document flow. Instead, it sits on its own layer separate from everything else. This is very useful: it means that we can create isolated UI features that don't interfere with the layout of other elements on the page. For example, popup information boxes, control menus, rollover panels, UI features that can be dragged and dropped anywhere on the page, and so on.
 
 Second, notice that the position of the element has changed. This is because {{cssxref("top")}}, {{cssxref("bottom")}}, {{cssxref("left")}}, and {{cssxref("right")}} behave in a different way with absolute positioning. Rather than positioning the element based on its relative position within the normal document flow, they specify the distance the element should be from each of the containing element's sides. So in this case, we are saying that the absolutely positioned element should sit 30px from the top of the "containing element" and 30px from the left. (In this case, the "containing element" is the **initial containing block**. See the section below for more information)
 

files/en-us/learn/css/first_steps/what_is_css/index.md

@@ -75,7 +75,7 @@ h1 {
 }
 ```
 
-- In the above example, the CSS rule opens with a {{Glossary("CSS Selector", "selector")}} . This _selects_ the HTML element that we are going to style. In this case, we are styling level one headings ({{htmlelement("h1")}}).
+- In the above example, the CSS rule opens with a {{Glossary("CSS Selector", "selector")}}. This _selects_ the HTML element that we are going to style. In this case, we are styling level one headings ({{htmlelement("h1")}}).
 - We then have a set of curly braces `{ }`.
 - Inside the braces will be one or more **declarations**, which take the form of **property** and **value** pairs. We specify the property (`color` in the above example) before the colon, and we specify the value of the property after the colon (`red` in this example).
 - This example contains two declarations, one for `color` and the other for `font-size`. Each pair specifies a property of the element(s) we are selecting ({{htmlelement("h1")}} in this case), then a value that we'd like to give the property.

files/en-us/learn/css/howto/create_fancy_boxes/index.md

@@ -279,7 +279,7 @@ So it's possible to create a wonderful effect when we mix all of this together.
 <div class="fancy">Hi! I want to be fancy.</div>
 ```
 
-Let's create some partial drop shadow effect.  The {{cssxref("box-shadow")}} property allow us to create inner light and a flat drop shadow effect, but with some little extra work it becomes possible to create a more natural geometry by using pseudo-element and the {{cssxref("transform")}} property.
+Let's create some partial drop shadow effect. The {{cssxref("box-shadow")}} property allow us to create inner light and a flat drop shadow effect, but with some little extra work it becomes possible to create a more natural geometry by using pseudo-element and the {{cssxref("transform")}} property.
 
 ```css
 .fancy {

files/en-us/learn/forms/basic_native_form_controls/index.md

@@ -114,7 +114,7 @@ It's worth noting that these widgets do not behave exactly like other form widge
 
 > **Note:** You can find the examples from this section on GitHub as [checkable-items.html](https://github.com/mdn/learning-area/blob/main/html/forms/native-form-widgets/checkable-items.html) ([see it live also](https://mdn.github.io/learning-area/html/forms/native-form-widgets/checkable-items.html)).
 
-For maximum usability/accessibility, you are advised to surround each list of related items in a {{htmlelement("fieldset")}}, with a {{htmlelement("legend")}} providing an overall description of the list.  Each individual pair of {{htmlelement("label")}}/{{htmlelement("input")}} elements should be contained in its own list item (or similar). The associated {{htmlelement('label')}} is generally placed immediately after the radio button or checkbox, with the instructions for the group of radio button or checkboxes generally being the content of the {{htmlelement("legend")}}. See the examples linked above for structural examples.
+For maximum usability/accessibility, you are advised to surround each list of related items in a {{htmlelement("fieldset")}}, with a {{htmlelement("legend")}} providing an overall description of the list. Each individual pair of {{htmlelement("label")}}/{{htmlelement("input")}} elements should be contained in its own list item (or similar). The associated {{htmlelement('label')}} is generally placed immediately after the radio button or checkbox, with the instructions for the group of radio button or checkboxes generally being the content of the {{htmlelement("legend")}}. See the examples linked above for structural examples.
 
 ### Check box
 

files/en-us/learn/front-end_web_developer/index.md

@@ -92,7 +92,7 @@ It is recommended that you have basic HTML knowledge before starting to learn CS
 
 #### How will I know I'm ready to move on?
 
-The assessments in each module are designed to test your knowledge of the subject matter.  Completing the assessments confirms that you are ready to move on to the next module.
+The assessments in each module are designed to test your knowledge of the subject matter. Completing the assessments confirms that you are ready to move on to the next module.
 
 #### Modules
 

files/en-us/learn/javascript/asynchronous/promises/index.md

@@ -58,7 +58,7 @@ console.log("Started request…");
 Here we are:
 
 1. calling the `fetch()` API, and assigning the return value to the `fetchPromise` variable
-2. immediately after, logging the `fetchPromise` variable. This should output something like: `Promise { <state>: "pending" }`, telling us that we have a `Promise` object, and it has a `state` whose value is `"pending"`.  The `"pending"` state means that the fetch operation is still going on.
+2. immediately after, logging the `fetchPromise` variable. This should output something like: `Promise { <state>: "pending" }`, telling us that we have a `Promise` object, and it has a `state` whose value is `"pending"`. The `"pending"` state means that the fetch operation is still going on.
 3. passing a handler function into the Promise's **`then()`** method. When (and if) the fetch operation succeeds, the promise will call our handler, passing in a {{domxref("Response")}} object, which contains the server's response.
 4. logging a message that we have started the request.
 

files/en-us/learn/javascript/client-side_web_apis/drawing_graphics/index.md

@@ -144,7 +144,7 @@ OK, our template is done and it's time to move on.
 
 As we said above, all drawing operations are done by manipulating a {{domxref("CanvasRenderingContext2D")}} object (in our case, `ctx`). Many operations need to be given coordinates to pinpoint exactly where to draw something — the top left of the canvas is point (0, 0), the horizontal (x) axis runs from left to right, and the vertical (y) axis runs from top to bottom.
 
-![Gridded graph paper with small squares covering its area with a steelblue square in the middle. The top left corner of the canvas is point (0, 0) of the canvas x-axis and y-axis. . The horizontal (x) axis runs from left to right denoting the width, and the vertical (y) axis runs from top to bottom denotes the height. The top left corner of the blue square is labeled as being a distance of x units from the y-axis and y units from the x-axis.](canvas_default_grid.png)
+![Gridded graph paper with small squares covering its area with a steelblue square in the middle. The top left corner of the canvas is point (0, 0) of the canvas x-axis and y-axis. The horizontal (x) axis runs from left to right denoting the width, and the vertical (y) axis runs from top to bottom denotes the height. The top left corner of the blue square is labeled as being a distance of x units from the y-axis and y units from the x-axis.](canvas_default_grid.png)
 
 Drawing shapes tends to be done using the rectangle shape primitive, or by tracing a line along a certain path and then filling in the shape. Below we'll show how to do both.
 
@@ -267,7 +267,7 @@ Let's draw an equilateral triangle on the canvas.
     - The side next to the 60 degree angle is called the **adjacent** — which we know is 50 pixels, as it is half of the line we just drew.
     - The side opposite the 60 degree angle is called the **opposite**, which is the height of the triangle we want to calculate.
 
-    ![A equilateral triangle pointing downwards with labeled angles and sides. The horizontal line at the top is labeled 'adjacent'. A perpendicular dotted line, from the middle of the adjacent line, labeled 'opposite', splits the triangle creating two equal right triangles.  The right side of the triangle is labeled the hypotenuse, as it is the hypotenuse of the right triangle formed by the line labeled 'opposite'. while all three-sided of the triangle are of equal length, the hypotenuse is the longest side of the right triangle.](trigonometry.png)
+    ![A equilateral triangle pointing downwards with labeled angles and sides. The horizontal line at the top is labeled 'adjacent'. A perpendicular dotted line, from the middle of the adjacent line, labeled 'opposite', splits the triangle creating two equal right triangles. The right side of the triangle is labeled the hypotenuse, as it is the hypotenuse of the right triangle formed by the line labeled 'opposite'. while all three-sided of the triangle are of equal length, the hypotenuse is the longest side of the right triangle.](trigonometry.png)
 
     One of the basic trigonometric formulae states that the length of the adjacent multiplied by the tangent of the angle is equal to the opposite, hence we come up with `50 * Math.tan(degToRad(60))`. We use our `degToRad()` function to convert 60 degrees to radians, as {{jsxref("Math.tan()")}} expects an input value in radians.
 

files/en-us/learn/javascript/client-side_web_apis/index.md

@@ -44,7 +44,7 @@ Basic knowledge of [HTML](/en-US/docs/Learn/HTML) and [CSS](/en-US/docs/Learn/CS
 - [Manipulating documents](/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Manipulating_documents)
   - : When writing web pages and apps, one of the most common things you'll want to do is manipulate web documents in some way. This is usually done by using the Document Object Model (DOM), a set of APIs for controlling HTML and styling information that makes heavy use of the {{domxref("Document")}} object. In this article, we'll look at how to use the DOM in detail, along with some other interesting APIs that can alter your environment in interesting ways.
 - [Fetching data from the server](/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Fetching_data)
-  - : Another very common task in modern websites and applications is retrieving individual data items from the server to update sections of a webpage without having to load an entirely new page. This seemingly small detail has had a huge impact on the performance and behavior of sites.  In this article, we'll explain the concept, and look at technologies that make it possible, such as {{domxref("XMLHttpRequest")}} and the [Fetch API](/en-US/docs/Web/API/Fetch_API).
+  - : Another very common task in modern websites and applications is retrieving individual data items from the server to update sections of a webpage without having to load an entirely new page. This seemingly small detail has had a huge impact on the performance and behavior of sites. In this article, we'll explain the concept, and look at technologies that make it possible, such as {{domxref("XMLHttpRequest")}} and the [Fetch API](/en-US/docs/Web/API/Fetch_API).
 - [Third party APIs](/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Third_party_APIs)
   - : The APIs we've covered so far are built into the browser, but not all APIs are. Many large websites and services such as Google Maps, Twitter, Facebook, PayPal, etc. provide APIs allowing developers to make use of their data (e.g. displaying your twitter stream on your blog) or services (e.g. displaying custom Google Maps on your site, or using Facebook login to log in your users). This article looks at the difference between browser APIs and 3rd party APIs and shows some typical uses of the latter.
 - [Drawing graphics](/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Drawing_graphics)

files/en-us/learn/performance/measuring_performance/index.md

@@ -12,7 +12,7 @@ tags:
 
 Measuring performance provides an important metric to help you asses the success of your app, site, or web service.
 
-For example, you can use performance metrics to determine how your app performs in comparison to a competitor or you can compare your app's performance across releases.  The metrics you choose to measure should be relevant to your users, site, and business goals. They should be collected and measured in a consistent manner and analyzed in a format that can be consumed and understood by non-technical stakeholders.
+For example, you can use performance metrics to determine how your app performs in comparison to a competitor or you can compare your app's performance across releases. The metrics you choose to measure should be relevant to your users, site, and business goals. They should be collected and measured in a consistent manner and analyzed in a format that can be consumed and understood by non-technical stakeholders.
 
 This article introduces web performance metrics that you can use to measure and optimize your site's performance.
 

files/en-us/learn/performance/why_web_performance/index.md

@@ -53,7 +53,7 @@ As an example, consider the loading experience of CNN.com, which at the time of
 
 A 22.6 MB site could take up to 83 seconds to load on a 3G network, with [`DOMContentLoaded`](/en-US/docs/Web/API/Document/DOMContentLoaded_event) (meaning the site's base HTML structure) at 31.86 seconds.
 
-And it isn't just the time taken to download that is a major problem. A lot of countries still have internet connections that bill per megabyte. Our example 22.6 MB CNN.com experience would cost about 11% of the average Indian's daily wage to download. From a mobile device in Northwest Africa, it might cost two days of an average salary.  And if this site were loaded on a US carrier's international roaming plan? The costs would make anyone cry. (See [how much your site costs to download](https://whatdoesmysitecost.com/).)
+And it isn't just the time taken to download that is a major problem. A lot of countries still have internet connections that bill per megabyte. Our example 22.6 MB CNN.com experience would cost about 11% of the average Indian's daily wage to download. From a mobile device in Northwest Africa, it might cost two days of an average salary. And if this site were loaded on a US carrier's international roaming plan? The costs would make anyone cry. (See [how much your site costs to download](https://whatdoesmysitecost.com/).)
 
 ### Improve conversion rates
 

files/en-us/learn/server-side/django/development_environment/index.md

@@ -359,7 +359,7 @@ py -3 -m django --version
 >
 > In Windows _Python 3_ scripts are launched by prefixing the command with `py -3`, although this can vary depending on your specific installation. Try omitting the `-3` modifier if you encounter any problems with commands. In Linux/macOS, the command is `python3.`
 
-> **Warning:** The rest of this **module** uses the _Linux_ command for invoking Python 3 (`python3`) . If you're working on _Windows_ replace this prefix with: `py -3`
+> **Warning:** The rest of this **module** uses the _Linux_ command for invoking Python 3 (`python3`). If you're working on _Windows_ replace this prefix with: `py -3`
 
 ## Other Python tools
 

files/en-us/learn/server-side/django/introduction/index.md

@@ -149,7 +149,7 @@ def index(request):
 
 > **Note:** A little bit of Python:
 >
-> - [Python modules](https://docs.python.org/3/tutorial/modules.html) are "libraries" of functions, stored in separate files, that we might want to use in our code. Here we import just the `HttpResponse` object from the `django.http` module so that we can use it in our view: `from django.http import HttpResponse` . There are other ways of importing some or all objects from a module.
+> - [Python modules](https://docs.python.org/3/tutorial/modules.html) are "libraries" of functions, stored in separate files, that we might want to use in our code. Here we import just the `HttpResponse` object from the `django.http` module so that we can use it in our view: `from django.http import HttpResponse`. There are other ways of importing some or all objects from a module.
 > - Functions are declared using the `def` keyword as shown above, with named parameters listed in brackets after the name of the function; the whole line ends in a colon. Note how the next lines are all **indented**. The indentation is important, as it specifies that the lines of code are inside that particular block (mandatory indentation is a key feature of Python, and is one reason that Python code is so easy to read).
 
 Views are usually stored in a file called **views.py**.

files/en-us/learn/server-side/express_nodejs/forms/create_bookinstance_form/index.md

@@ -159,7 +159,7 @@ The view structure and behavior is almost the same as for the **book_form.pug**
 
 Run the application and open your browser to `http://localhost:3000/`. Then select the _Create new book instance (copy)_ link. If everything is set up correctly, your site should look something like the following screenshot. After you submit a valid `BookInstance`, it should be saved and you'll be taken to the detail page.
 
-![Create BookInstance of the Local library application screenshot from localhost:3000.  The page is divided into two columns. The narrow left column has a vertical navigation bar with 10 links separated into two sections by a light-colored horizontal line. The top section link to already created data. The bottom links go to create new data forms. The wide right column has the create book instance form with a 'Create BookInstance' heading and four input fields labeled 'Book', 'Imprint', 'Date when book available' and 'Status'. The form is filled. There is a 'Submit' button at the bottom of the form.](locallibary_express_bookinstance_create_empty.png)
+![Create BookInstance of the Local library application screenshot from localhost:3000. The page is divided into two columns. The narrow left column has a vertical navigation bar with 10 links separated into two sections by a light-colored horizontal line. The top section link to already created data. The bottom links go to create new data forms. The wide right column has the create book instance form with a 'Create BookInstance' heading and four input fields labeled 'Book', 'Imprint', 'Date when book available' and 'Status'. The form is filled. There is a 'Submit' button at the bottom of the form.](locallibary_express_bookinstance_create_empty.png)
 
 ## Next steps
 

files/en-us/learn/server-side/express_nodejs/mongoose/index.md

@@ -376,7 +376,7 @@ Above we've defined the query conditions in the `find()` method. We can also do
 Athlete.
   find().
   where('sport').equals('Tennis').
-  where('age').gt(17).lt(50).  //Additional where query
+  where('age').gt(17).lt(50). // Additional where query
   limit(5).
   sort({ age: -1 }).
   select('name age').