Fix typo in the number of properties (#1208)

common-content/en/module/js2/key-values/index.md

@@ -27,7 +27,7 @@ Each **property** is an association between a key and a value.
 };
 ```
 
-In the {{<tooltip title="object literal">}} An object literal is an object defined by writing a comma-separated list of key-value pairs inside of curly braces.{{</tooltip>}} above, there are 3 properties. The first property consists of `firstName` and `"Francesco"`. `firstName` is the **key**, `"Francesco"` is the **value** associated with the key `firstName`.
+In the {{<tooltip title="object literal">}} An object literal is an object defined by writing a comma-separated list of key-value pairs inside of curly braces.{{</tooltip>}} above, there are 4 properties. The first property consists of `firstName` and `"Francesco"`. `firstName` is the **key**, `"Francesco"` is the **value** associated with the key `firstName`.
 
 In object literals, each **key-value pair** is separated by a comma.