Added discussion label change to release notes

docs/en_us/release_notes/source/07-10-2014.rst

@@ -38,6 +38,13 @@ edX Learning Management System
   in the discussion forum topic list sometimes appeared with unexpected
   formatting. This bug has been fixed. (FOR-578)
 
+* The Discussions user interface is updated to include labels for pinned and
+  staff-initiated threads in the discussion list, as shown in the following
+  example:
+
+  .. image:: images/discussion_labels.png
+   :alt: Image of discussions with Pinned and By: Staff labels
+
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