Fix typo on front page

index.html

@@ -85,7 +85,7 @@
       <li><a href="demo/runmode.html">Stand-alone highlighting</a></li>
       <li><a href="demo/fullscreen.html">Full-screen editing</a></li>
       <li><a href="demo/changemode.html">Mode auto-changing</a></li>
-      <li><a href="demo/visibletabs.html">Visible tabls</a></li>
+      <li><a href="demo/visibletabs.html">Visible tabs</a></li>
       <li><a href="demo/emacs.html">Emacs keybindings</a></li>
     </ul>