Merge branch 'no-comment-button-on-discussion-diffs-8-10' into '8-10-stable'

[8.10] Don't show comment button in gutter of diffs on MR discussion tab

`8-10-stable` counterpart to https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5492

See merge request !5493

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
 
 v 8.10.2 (unreleased)
+  - Don't show comment button in gutter of diffs on MR discussion tab
 
 v 8.10.1
   - Refactor repository storages documentation. !5428

app/assets/javascripts/files_comment_button.js.coffee

@@ -16,7 +16,7 @@ class @FilesCommentButton
 
     debounce = _.debounce @render, DEBOUNCE_TIMEOUT_DURATION
 
-    $(document)
+    $(@filesContainerElement)
       .off 'mouseover', LINE_COLUMN_CLASSES
       .off 'mouseleave', LINE_COLUMN_CLASSES
       .on 'mouseover', LINE_COLUMN_CLASSES, debounce