Added docs for enhanced link tag

Merge pull request 6990

docs/_docs/configuration.md

@@ -689,11 +689,6 @@ liquid:
   strict_variables: false
 
 # Markdown Processors
-rdiscount:
-  extensions: []
-
-redcarpet:
-  extensions: []
 
 kramdown:
   auto_ids:      true
@@ -728,50 +723,6 @@ mutually exclusive.
 The various Markdown renderers supported by Jekyll sometimes have extra options
 available.
 
-### Redcarpet
-
-Redcarpet can be configured by providing an `extensions` sub-setting, whose
-value should be an array of strings. Each string should be the name of one of
-the `Redcarpet::Markdown` class's extensions; if present in the array, it will
-set the corresponding extension to `true`.
-
-Jekyll handles two special Redcarpet extensions:
-
-- `no_fenced_code_blocks` --- By default, Jekyll sets the `fenced_code_blocks`
-extension (for delimiting code blocks with triple tildes or triple backticks)
-to `true`, probably because GitHub's eager adoption of them is starting to make
-them inescapable. Redcarpet's normal `fenced_code_blocks` extension is inert
-when used with Jekyll; instead, you can use this inverted version of the
-extension for disabling fenced code.
-
-Note that you can also specify a language for highlighting after the first
-delimiter:
-
-        ```ruby
-        # ...ruby code
-        ```
-
-With both fenced code blocks and highlighter enabled, this will statically
-highlight the code; without any syntax highlighter, it will add a
-`class="LANGUAGE"` attribute to the `<code>` element, which can be used as a
-hint by various JavaScript code highlighting libraries.
-
-- `smart` --- This pseudo-extension turns on SmartyPants, which converts
-  straight quotes to curly quotes and runs of hyphens to em (`---`) and en (`--`) dashes.
-
-All other extensions retain their usual names from Redcarpet, and no renderer
-options aside from `smart` can be specified in Jekyll. [A list of available
-extensions can be found in the Redcarpet README file.][redcarpet_extensions]
-Make sure you're looking at the README for the right version of
-Redcarpet: Jekyll currently uses v3.2.x. The most commonly used
-extensions are:
-
-- `tables`
-- `no_intra_emphasis`
-- `autolink`
-
-[redcarpet_extensions]: https://github.com/vmg/redcarpet/blob/v3.2.2/README.markdown#and-its-like-really-simple-to-use
-
 ### Custom Markdown Processors
 
 If you're interested in creating a custom markdown processor, you're in luck! Create a new class in the `Jekyll::Converters::Markdown` namespace:

docs/_docs/templates.md

@@ -588,6 +588,23 @@ One major benefit of using the `link` or `post_url` tag is link validation. If t
 
 Note you cannot add filters to `link` tags. For example, you cannot append a string using Liquid filters, such as `{% raw %}{% link mypage.html | append: "#section1" %} {% endraw %}`. To link to sections on a page, you will need to use regular HTML or Markdown linking techniques.
 
+The name of the file you want to link can be specified as a variable instead of an actual file name. For example, suppose you defined a variable in your page's front matter like this:
+
+```yaml
+---
+title: My page
+my_variable: footer_company_a.html
+---
+```
+
+You could then reference that variable in your link:
+
+```liquid
+{% raw %}{% link {{ page.my_variable }} %}{% endraw %}
+```
+
+In this example, the link would add link to the file `footer_company_a.html`.
+
 ### Linking to posts
 
 If you want to include a link to a post on your site, the `post_url` tag will generate the correct permalink URL for the post you specify.