website: Add wiki link to navigation bar (#3424)

Related to #3423

docs/templates/shared/_navbar.html.j2

@@ -25,6 +25,7 @@
             <li class="nav-item"><a class="nav-link" href="https://github.com/jqlang/jq/issues" target="_blank" rel="noopener">Issues</a></li>
             <li class="nav-item"><a class="nav-link" href="https://play.jqlang.org" rel="noopener">Try online!</a></li>
             <li class="nav-item"><a class="nav-link" href="https://raw.githubusercontent.com/jqlang/jq/master/NEWS.md" target="_blank" rel="noopener">News</a></li>
+            <li class="nav-item"><a class="nav-link" href="https://github.com/jqlang/jq/wiki" target="_blank" rel="noopener">Wiki</a></li>
           </ul>
         </div>
         {%- if navitem.startswith('manual') %}