Merge pull request #2175 from edx/andya/typo

Fix typo in the announcement template

common/lib/xmodule/xmodule/templates/html/announcement.yaml

@@ -15,7 +15,7 @@ data: |
       	       given, and so detailed explainations in this section will benefit the most concientious.
       	       Any essential information should be extremely quickly summarized in the primary section for skimmers.</p>
       	       <p><h3>Star Forum Poster</h3>
-      	       Students appriciate knowing that the course staff is reading what they post, and one of several ways
+      	       Students appreciate knowing that the course staff is reading what they post, and one of several ways
       	       that you can do this is by acknowledging the star posters in your announcements.
       	       </p>
       </section>