doc improvement.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@5744 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/model/listeners/RunListener.java

@@ -32,7 +32,8 @@ public abstract class RunListener<R extends Run> implements ExtensionPoint {
      *      The completed build.
      * @param listener
      *      The listener for this build. This can be used to produce log messages, for example,
-     *      which becomes a part of the "console output" of this build.
+     *      which becomes a part of the "console output" of this build. But when this method runs,
+     *      the build is considered completed, so its status cannot be changed anymore.
      */
     public void onCompleted(R r, TaskListener listener) {}