[JENKINS-16468] Linking in changelog.

changelog.html

@@ -360,6 +360,7 @@ Upcoming changes</a>
     Display non-default update site URLs in the Advanced tab of Plugin Manager. (Currently not configurable from this UI.)
   <li class=rfe>
     Fixed the lock contention problem on <tt>Queue.getItems()</tt>
+    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-16468">issue 16468</a>)
   <li class=rfe>
     Put slave back online automatically, if there's enough disk space again 
     (<a href="https://github.com/jenkinsci/jenkins/pull/514">pull 514</a>)