fix STOMP docs link

Author: deadtrickster

site/stomp.md

@@ -19,7 +19,7 @@ limitations under the License.
 
 ## <a id="overview" class="anchor" href="#overview">Overview</a>
 
-RabbitMQ supports [STOMP](http://stomp.github.com) via a plugin that ships
+RabbitMQ supports [STOMP](http://stomp.github.io) via a plugin that ships
 in the core distribution. The plugin supports STOMP versions 1.0 through [1.2](http://stomp.github.com/stomp-specification-1.2.html)
 with some [extensions and restrictions](#extensions-and-restrictions).