[view,ux][xs]: add title to document / row limit input giving instructions on use.

src/view.js

@@ -55,7 +55,7 @@ my.DataExplorer = Backbone.View.extend({
       </ul> \
       <div class="pagination"> \
         <form class="display-count"> \
-          Showing 0 to <input name="displayCount" type="text" value="{{displayCount}}" /> of  <span class="doc-count">{{docCount}}</span> \
+          Showing 0 to <input name="displayCount" type="text" value="{{displayCount}}" title="Edit and hit enter to change the number of rows displayed" /> of  <span class="doc-count">{{docCount}}</span> \
         </form> \
       </div> \
     </div> \