docs: add environment variables to sidebar links (#1467)

Co-authored-by: Jordan Woods <13803242+jorwoods@users.noreply.github.com>

Author: jorwoods

_includes/docs_menu.html

@@ -22,6 +22,9 @@
         <li>
             <a href="{{ site.baseurl }}/docs/filter-sort">Filter and Sort</a>
         </li>
+        <li>
+            <a href="{{ site.baseurl }}/docs/environment-variables">Environment Variables</a>
+        </li>
         <li>
             <a href="{{ site.baseurl }}/docs/samples">Samples</a>
         </li>