Merge branch 'remove-gap-between-mr-tabs-and-file-header' into 'master'

Remove extra space between MR tab bar and sticky file headers

See merge request gitlab-org/gitlab-ce!24238

app/assets/stylesheets/pages/diff.scss

@@ -9,7 +9,7 @@
     @media (min-width: map-get($grid-breakpoints, md)) {
       position: -webkit-sticky;
       position: sticky;
-      top: 92px;
+      top: $header-height + 51px;
       margin-left: -1px;
       border-left: 1px solid $border-color;
       z-index: 102;

changelogs/unreleased/remove-gap-between-mr-tabs-and-file-header.yml

+---
+title: Remove extra space between MR tab bar and sticky file headers
+merge_request:
+author:
+type: fixed