Add disable item to demo

Author: muan

examples/index.html

@@ -15,7 +15,7 @@
     </label>
     <ul role="listbox" id="list-id">
       <li id="baymax" role="option">Baymax</li>
-      <li><del>BB-8</del></li>
+      <li id="bb-8" role="option" aria-disabled="true"><del>BB-8</del></li>
       <li id="hubot" role="option">Hubot</li>
       <li id="r2-d2" role="option">R2-D2</li>
     </ul>