Merge pull request #334 from CodeSandwich/custom_header_footer

Add custom header and footer include files

docs/configuration.md

@@ -87,10 +87,13 @@ heading_anchors: true
 ## Footer content
 
 ```yaml
-# Footer content 
+# Footer content
 # appears at the bottom of every page's main content
 footer_content: "Copyright &copy; 2017-2019 Patrick Marsceill. Distributed by an <a href=\"https://github.com/pmarsceill/just-the-docs/tree/master/LICENSE.txt\">MIT license.</a>"
 
+Note: This option is deprecated and will be removed in a future major release. Please use `_includes/footer_custom.html` for more robust
+markup / liquid-based content.
+
 # Footer last edited timestamp
 last_edit_timestamp: true # show or hide edit time - page must have `last_modified_date` defined in the frontmatter
 last_edit_time_format: "%b %e %Y at %I:%M %p" # uses ruby's time format: https://ruby-doc.org/stdlib-2.7.0/libdoc/time/rdoc/Time.html
@@ -104,6 +107,8 @@ gh_edit_branch: "master" # the branch that your docs is served from
 gh_edit_view_mode: "tree" # "tree" or "edit" if you want the user to jump into the editor immediately
 ```
 
+_note: `footer_content` is deprecated, but still supported. For a better experience we have moved this into an include called `_includes/footer_custom.html` which will allow for robust markup / liquid-based content._
+
 - the "page last modified" data will only display if a page has a key called `last_modified_date`, formatted in some readable date format
 - `last_edit_time_format` uses Ruby's DateTime formatter; see examples and more information [at this link.](https://apidock.com/ruby/DateTime/strftime)
 - `gh_edit_repository` is the URL of the project's GitHub repository