Revert "set icon color"

This reverts commit c42aee49956bd8082defa09555260207d43bb225.

src/client/styles/scss/_comment.scss

@@ -44,7 +44,6 @@
     .page-comment-revision svg {
       width: 16px;
       height: 16px;
-      fill: $primary;
     }
   }