Add custom header and footer include files

_includes/footer_custom.html

@@ -0,0 +1,3 @@
+{%- if site.footer_content -%}
+  <p class="text-small text-grey-dk-000 mb-0">{{ site.footer_content }}</p>
+{%- endif -%}

_layouts/default.html

@@ -65,6 +65,7 @@ layout: table_wrappers
           <div id="search-results" class="search-results"></div>
         </div>
       {% endif %}
+      {% include header_custom.html %}
       {% if site.aux_links %}
         <nav aria-label="Auxiliary" class="aux-nav">
           <ul class="aux-nav-list">
@@ -119,15 +120,17 @@ layout: table_wrappers
           </ul>
         {% endif %}
 
-        {% if site.footer_content != nil or site.last_edit_timestamp or site.gh_edit_link %}
+        {% capture footer_custom %}
+          {%- include footer_custom.html -%}
+        {% endcapture %}
+        {% if footer_custom != "" or site.last_edit_timestamp or site.gh_edit_link %}
           <hr>
           <footer>
             {% if site.back_to_top %}
               <p><a href="#top" id="back-to-top">{{ site.back_to_top_text }}</a></p>
             {% endif %}
-            {% if site.footer_content != nil %}
-              <p class="text-small text-grey-dk-000 mb-0">{{ site.footer_content }}</p>
-            {% endif %}
+
+            {{ footer_custom }}
 
             {% if site.last_edit_timestamp or site.gh_edit_link %}
               <div class="d-flex mt-2">

docs/configuration.md

@@ -86,10 +86,12 @@ 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>"
 
+This option is deprecated and will be removed in a future major release. Please use `footer_custom.html`.
+
 # 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