Fix JS in old IEs by removing trailing comma

* Was fine on live because comma was stripped out
* Made it difficult to test new javascript features on IE7

Aside: This jQuery plugin has a few reported problems related to older versions of IE. The version after the one we're using is a "complete rewrite", without any real docs. https://github.com/mistic100/jquery-highlighttextarea/issues?page=1&state=closed