[feat] Support contributingUrl param

layouts/partials/community_links.html

@@ -1,4 +1,5 @@
 {{ $links := .Site.Params.links -}}
+{{ $contribUrl := .Params.contributingUrl | default "docs/contribution-guidelinesx" -}}
 
 <section class="row td-box td-box--white td-box--height-auto linkbox">
   <div class="col-xs-12 col-sm-6 col-md-6 col-lg-6">
@@ -16,7 +17,7 @@ <h2>{{ T "community_develop" }}</h2>
     {{ end }}
     <p>
       {{ T "community_how_to" . }}
-      <a href="{{ "docs/contribution-guidelines" | relURL }}">{{ T "community_guideline" }}</a>.
+      <a href="{{ $contribUrl | relURL }}">{{ T "community_guideline" }}</a>.
     </p>
   </div>
 </section>

userguide/content/en/docs/adding-content/content.md

@@ -599,6 +599,16 @@ params:
 
 If you're creating your own site and want to add a page using this template, add a `/community/_index.md` file in your content root directory. If you've copied the example site and *don't* want a community page, just delete the `/content/en/community/` directory in your project repo.
 
+By default, Docsy layouts assume that your project's contributing page is found
+at `<baseURL>/docs/contribution-guidelines`. To specify another URL, add it to
+the front matter of `/community/_index.md` as illustrated next. The URL can be
+an external URL or a local path:
+
+```yaml
+params:
+  contributingUrl: docs/contributing/
+```
+
 ## Adding static content
 
 You may want to serve some non-Hugo-built content along with your site: for example, if you have generated reference docs using Doxygen, Javadoc, or other doc generation tools.