Clarify that async: false can still be used, but not with Deferred.

Author: dmethvin

entries/jQuery.ajax.xml

@@ -19,7 +19,7 @@
         <desc>The content type sent in the request header that tells the server what kind of response it will accept in return. If the <code>accepts</code> setting needs modification, it is recommended to do so once in the <code>$.ajaxSetup()</code> method.</desc>
       </option>
       <option default="true" name="async" type="Boolean">
-        <desc>By default, all requests are sent asynchronously (i.e. this is set to <code>true</code> by default). If you need synchronous requests, set this option to <code>false</code>. Cross-domain requests and <code>dataType: "jsonp"</code> requests do not support synchronous operation. Note that synchronous requests may temporarily lock the browser, disabling any actions while the request is active. <strong>As of jQuery 1.8, the use of <code> async: false </code> is deprecated.</strong></desc>
+        <desc>By default, all requests are sent asynchronously (i.e. this is set to <code>true</code> by default). If you need synchronous requests, set this option to <code>false</code>. Cross-domain requests and <code>dataType: "jsonp"</code> requests do not support synchronous operation. Note that synchronous requests may temporarily lock the browser, disabling any actions while the request is active. <strong>As of jQuery 1.8, the use of <code> async: false </code> with jqXHR ($.Deferred) is deprecated; you must use the complete/success/error callbacks.</strong></desc>
       </option>
       <option name="beforeSend" type="Function">
         <argument name="jqXHR" type="jqXHR"/>