more documentation on upgrading and change events.

index.html

@@ -524,6 +524,8 @@
       <li>
         <tt>model.set</tt> will no longer trigger change events when setting a value
         with <tt>{silent: true}</tt> then setting it back to it's original value.
+        Similarly, after changing an attribute silently, that <tt>change:attribute</tt>
+        event <i>will</i> fire during the next change.
       </li>
     </ul>