Update jQuery to v1.11.3.

docs/_includes/footer.html

@@ -40,6 +40,6 @@
   }(document, "script", "twitter-wjs"));
 </script>
 
-<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>
+<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
 <script src="/dist/js/ratchet.min.js"></script>
 <script src="/assets/js/docs.min.js"></script>