Widget demo: Remove link to planning wiki.

demos/widget/default.html

@@ -173,7 +173,6 @@
 <div class="demo-description">
 <p>This demo shows a simple custom widget built using the widget factory (jquery.ui.widget.js).</p>
 <p>The three boxes are initialized in different ways. Clicking them changes their background color. View source to see how it works, its heavily commented</p>
-<p><a href="http://wiki.jqueryui.com/w/page/12138135/Widget-factory">For more details on the widget factory, visit the jQuery UI planning wiki.</a></p>
 </div>
 </body>
 </html>