Darken file names

services/web/public/stylesheets/app/editor/file-tree.less

@@ -33,7 +33,7 @@ aside#file-tree {
 			line-height: 2.6;
 
 			.entity-name {
-				color: @gray-dark;
+				color: @gray-darker;
 				cursor: pointer;
 				white-space: nowrap;
 				overflow: hidden;