Switch to side-by-side view

--- a/website/doc.html
+++ b/website/doc.html
@@ -33,7 +33,8 @@
       <h1>Recoll user manual</h1>
       
       <ul>
-      <li><a href="usermanual/index.html">English</a></li>
+      <li><a href="usermanual/index.html">English, HTML</a></li>
+      <li><a href="usermanual/recoll_user_manual.pdf">English, PDF</a></li>
       <li><a href="http://mcz.altervista.org/Pagine/usermanual-italian.html">
 	  Italian (rather old)</a></li>
       </ul>