Automatically stuff reference in commit message (#36844)

* Automatically stuff reference in commit message

So we probably want to track which edits were performed through the
Github interface, and this change automatically adds a label to the
commit message.

```yaml
<!--- Your description here -->

+label: docsite_pr
```

Eventually this allows to (on regular basis) list the changes from
documentation readers and process them in a separate process.

docs/docsite/_themes/sphinx_rtd_theme/breadcrumbs.html

@@ -3,11 +3,11 @@
   <li><a href="">{{ title }}</a></li>
   {% if pagename.endswith('_module') %}
     <li class="wy-breadcrumbs-aside">
-      <a href="https://github.com/ansible/ansible/edit/devel/lib/ansible/modules/{{ meta.get('source', '') }}" class="icon icon-github"> Edit on GitHub</a>
+      <a href="https://github.com/ansible/ansible/edit/devel/lib/ansible/modules/{{ meta.get('source', '') }}?description=%3C!---%20Your%20description%20here%20--%3E%0A%0A+label:%20docsite_pr" class="icon icon-github"> Edit on GitHub</a>
     </li>
   {% elif (not 'list_of' in pagename) and (not 'category' in pagename) %}
     <li class="wy-breadcrumbs-aside">
-      <a href="https://github.com/ansible/ansible/edit/devel/docs/docsite/rst/{{ pagename }}.rst" class="icon icon-github"> Edit on GitHub</a>
+      <a href="https://github.com/ansible/ansible/edit/devel/docs/docsite/rst/{{ pagename }}.rst?description=%3C!---%20Your%20description%20here%20--%3E%0A%0A+label:%20docsite_pr" class="icon icon-github"> Edit on GitHub</a>
     </li>
   {% endif %}
 </ul>

docs/templates/plugin.rst.j2

@@ -318,4 +318,4 @@ please refer to this `Knowledge Base article <https://access.redhat.com/articles
 {%   endif %}
 {% endif %}
 
-If you notice any issues in this documentation you can ``edit this document <https://github.com/ansible/ansible/edit/devel/lib/ansible/modules/@{ source }@>`` to improve it.
+If you notice any issues in this documentation you can ``edit this document <https://github.com/ansible/ansible/edit/devel/lib/ansible/modules/@{ source }@?description=%3C!---%20Your%20description%20here%20--%3E%0A%0A+label:%20docsite_pr>`` to improve it.