docs: Improve data explanation, more links

docs/data.md

@@ -6,9 +6,10 @@ data:
 ---
 ## Data Files
 
-Cobalt supports loading [yaml](http://yaml.org), [json](http://json.org), and
-[toml](https://github.com/toml-lang/toml.html) from [`_data`](/docs/directory)
-and making it available as [`site.data.<DIR>.<FILE>`](/docs/variables).
+Cobalt reads data from any [yaml](http://yaml.org), [json](http://json.org), and
+[toml](https://github.com/toml-lang/toml.html) files in the [`_data` directory](/docs/directory)
+and merges them into the [`site.data`](/docs/variables) variable, making
+them available as `site.data.<DIR>.<FILE>`.
 
 ### Example
 
@@ -17,7 +18,7 @@ In `_data/animals/dogs.yml`:
 - name: Corgi
 - name: Malamute
 ```
-which can be accessed via `site.data.animals.dogs`.
+which liquid templates can access via `site.data.animals.dogs`.
 
 You can now render the list in a template:
 ```html

docs/directory.md

@@ -44,7 +44,7 @@ File / Directory | Description
 `_cobalt.yml`    | Site-wide [configuration](/docs/config) file
 `_layouts`       | [Templates](/docs/layouts) that wrap pages.  The layout is chosen in the [frontmatter](/docs/pages)
 `_includes`      | Liquid snippets of content to be shared among [layouts](/docs/layouts) or pages.
-`_data`          | Data files that will be loaded as part of the `{%raw%}{{ site.data }}{%endraw%}` variable.
+`_data`          | [Data files](/docs/data) in this directory are loaded as part of the `{%raw%}{{ site.data }}{%endraw%}` [variable](/docs/variables).
 `_sass`          | Sass snippets that can be imported into your `.scss` files.
 `_site`          | The output directory of cobalt.  Can be modified in [`_cobalt.yml`](/docs/config).
 `_defaults`      | `cobalt new` initializes files from here based on the collection name.

docs/variables.md

@@ -39,7 +39,7 @@ Variable           |  Format | Description
 `site.title`       |  String | The title of the entire site, see [`_cobalt.yml`](/docs/config).
 `site.description` |  String | The description of the entire site, see [`_cobalt.yml`](/docs/config).
 `site.base_url`    |  String | The URL of your site, see [`_cobalt.yml`](/docs/config).  This is helpful for making absolute URLs, particularly when run within [`cobalt serve`](/docs/usage).
-`site.data`        |  Object  | The merged result of [`_data`](/docs/directory) and [`site: data`](/docs/config).
+`site.data`        |  Object  | The merged result of [data files](/docs/data) in the [`_data`](/docs/directory) directory and [`site: data`](/docs/config) in `_cobalt.yml`.
 `site.time`        | DateTime | A `liquid_core::model::DateTime` representing the time of the website re-generation.
 
 ### Page Variables