docs: add link to cli in mobile view (wren-lang#1107)

Author: mgred

doc/site/template.html

@@ -100,6 +100,7 @@ <h2>reference</h2>
         <td>
           <ul>
             <li><a href="modules">API/Modules</a></li>
+            <li><a href="cli">Wren CLI</a></li>
             <li><a href="embedding">Embedding</a></li>
             <li><a href="performance.html">Performance</a></li>
             <li><a href="qa.html">Q &amp; A</a></li>