Merge branch 'winh-dropdown-item-style' into 'master'

Apply existing dropdown item styles to .dropdown-item class

See merge request gitlab-org/gitlab-ce!23663

app/assets/stylesheets/framework/dropdowns.scss

@@ -290,6 +290,10 @@
     }
   }
 
+  .dropdown-item {
+    @include dropdown-link;
+  }
+
   .divider {
     height: 1px;
     margin: #{$grid-size / 2} 0;