Improve link to comment targets on dashboard

app/assets/stylesheets/gitlab_bootstrap/buttons.scss

 .btn {
   @include linear-gradient(#f7f7f7, #d5d5d5);
-  border-color: #aaa;
+  border-color: #BBB;
   &:hover {
     @include bg-gray-gradient;
     border-color: #bbb;

app/views/events/event/_note.html.haml

 .event-title
   %span.author_name= link_to_author event
-  %span.event_label commented on #{event.note_target_type}
+  %span.event_label commented on
   - if event.note_target
     - if event.note_commit?
+      = event.note_target_type
       = link_to event.note_short_commit_id, project_commit_path(event.project, event.note_commit_id), class: "commit_short_id"
     - else
       = link_to [event.project, event.note_target] do
-        %strong= truncate event.note_target_id
+        %strong
+          #{event.note_target_type} ##{truncate event.note_target_id}
   - elsif event.wall_note?
-    -# nothing here
+    = link_to 'wall', wall_project_path(event.project)
   - else
     %strong (deleted)
   at