add link to forge (#1102)

Author: anton-iskryzhytskyi

locales/en-US/common.ftl

@@ -42,6 +42,7 @@ nav-logo-alt = Rust Logo
 footer-doc = Documentation
 footer-ask = Ask a Question on the Users Forum
 footer-status = Check Website Status
+footer-sup-doc = Rust Forge (Contributor Documentation)
 footer-policies = Terms and policies
 footer-coc = Code of Conduct
 footer-licenses = Licenses

templates/components/footer.hbs

@@ -5,6 +5,7 @@
         <h4>{{fluent "footer-get-help"}}</h4>
         <ul>
           <li><a href="{{baseurl}}/learn">{{fluent "footer-doc"}}</a></li>
+          <li><a href="http://forge.rust-lang.org">{{fluent "footer-sup-doc"}}</a></li>
           <li><a href="https://users.rust-lang.org">{{fluent "footer-ask"}}</a></li>
           <li><a href="http://ping.rust-lang.org">{{fluent "footer-status"}}</a></li>
         </ul>