Add experiments link to the options page

This link points to the experiments page, and is only shown in
non-release versions of the extension.

Change-Id: I09db9e6ded29be7f6f03f97378cd9311f88d40d3
diff --git a/src/options/options.html b/src/options/options.html
index f4f6651..37f7e7f 100644
--- a/src/options/options.html
+++ b/src/options/options.html
@@ -9,6 +9,15 @@
   </head>
   <body>
     <main>
+      <div class="experiments-link" hidden>
+        <!--
+          Material Design Icon - social/science
+           - LICENSE: Apache License Version 2.0
+           - Source: https://github.com/google/material-design-icons/
+           - Author: Google LLC
+        -->
+        <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><g><rect fill="none" height="24" width="24"/></g><g><path d="M13,11.33L18,18H6l5-6.67V6h2 M15.96,4H8.04C7.62,4,7.39,4.48,7.65,4.81L9,6.5v4.17L3.2,18.4C2.71,19.06,3.18,20,4,20h16 c0.82,0,1.29-0.94,0.8-1.6L15,10.67V6.5l1.35-1.69C16.61,4.48,16.38,4,15.96,4L15.96,4z"/></g></svg>
+      </div>
       <a href="https://gerrit.avm99963.com/plugins/gitiles/infinitegforums/+/master/docs/features.md" target="_blank" class="features-link">
         <!--
           Material Design Icon - action/help_outline