Added a warning if the current topic is hidden from search engines

A non-indexed topic won't be displayed in search results—but the setting for this is hidden behind the _Navigation_ tab. The warning elevates attention to this, while keeping the setting under _Navigation_, where it makes logical sense.

Author: JeremyCaney

OnTopic.Editor.AspNetCore/Areas/Editor/Views/Editor/Edit.cshtml

@@ -44,6 +44,12 @@
           <strong>Note:</strong> This topic is currently hidden and will not be displayed in the site navigation. Customers can still access it, and it will still show up in search results.
         </div>
       }
+      @if (Model.Topic.NoIndex) {
+        <div class="alert alert-warning" role="alert">
+          <button type="button" class="close" data-dismiss="alert"><span aria-hidden="true">×</span><span class="sr-only">Close</span></button>
+          <strong>Note:</strong> This topic is currently hidden from search engines. Customers can still access it, but it won't show up in search results.
+        </div>
+      }
       @if (!String.IsNullOrWhiteSpace(Model.ContentTypeDescriptor.Description)) {
         <div class="alert alert-primary" role="alert">
           @Model.ContentTypeDescriptor.Description