added link to loader.html

Author: agcolom

docs/pages/popup/index.html

@@ -238,6 +238,7 @@ <h3>More in this section</h3>
 								<li><a href="../page-titles.html">Page titles</a></li>
 								<li><a href="../page-links.html">Linking pages</a></li>
 								<li><a href="../page-transitions.html" data-ajax="false">Page transitions</a></li>
+								<li><a href="../loader.html">Page loading widget</a></li>
 								<li><a href="../page-dialogs.html">Dialogs</a></li>
 								<li data-theme="a"><a href="index.html">Popups</a></li>
 								<li><a href="../page-cache.html">Prefetching &amp; caching pages</a></li>