Switch to side-by-side view

--- a/website/helpernotes.html
+++ b/website/helpernotes.html
@@ -28,7 +28,7 @@
 
         <li><a href="download.html">Downloads</a></li>
 
-        <li><a href="usermanual/index.html">User manual</a></li>
+        <li><a href="doc.html">User manual</a></li>
 
         <li><a href="index.html#support">Support</a></li>