adjust forbidden page

src/server/views/widget/forbidden_content.html

@@ -20,10 +20,10 @@
     </div>
   </div>
 
-  <ul class="nav nav-tabs hidden-print">
+  <ul class="nav nav-tabs hidden-print" role="tablist">
     <li class="nav-item grw-nav-main-left-tab">
-      <a class="nav-link active" href="#revision-body" data-toggle="tab">
-        <i class="icon-notebook"></i> List 
+      <a class="nav-link active" role="tab" href="#revision-body" data-toggle="tab">
+        <i class="icon-notebook"></i> List
       </a>
     </li>
   </ul>