3.2 sidebar: link to 3.3, not 3.1

Doc/tools/sphinxext/indexsidebar.html

@@ -3,7 +3,7 @@
 	    <h3>Docs for other versions</h3>
 	    <ul>
 	      <li><a href="http://docs.python.org/2.7/">Python 2.7 (stable)</a></li>
-	      <li><a href="http://docs.python.org/3.1/">Python 3.1 (stable)</a></li>
+	      <li><a href="http://docs.python.org/3.3/">Python 3.3 (in development)</a></li>
               <li><a href="http://www.python.org/doc/versions/">Old versions</a></li>
             </ul>