Add missing label

cps/templates/layout.html

@@ -56,7 +56,8 @@
         {% if g.user.is_authenticated or g.user.is_anonymous() %}
           <form class="navbar-form navbar-left" role="search" action="{{url_for('search')}}" method="GET">
             <div class="form-group input-group input-group-sm">
-              <input type="text" class="form-control" name="query" placeholder="{{_('Search')}}">
+              <label for="query" class="sr-only">{{_('Search')}}</label>
+              <input type="text" class="form-control" id="query" name="query" placeholder="{{_('Search')}}">
               <span class="input-group-btn">
                 <button type="submit" class="btn btn-default">{{_('Go!')}}</button>
               </span>