Add scroll-margin-top to account for sticky header (#16269)

Fixes #16263

Co-authored-by: zeripath <art27@cantab.net>

web_src/js/index.js

@@ -1343,7 +1343,7 @@ function initPullRequestReview() {
         $(`#code-comments-${id}`).removeClass('hide');
         $(`#code-preview-${id}`).removeClass('hide');
         $(`#hide-outdated-${id}`).removeClass('hide');
-        $(window).scrollTop(commentDiv.offset().top);
+        commentDiv[0].scrollIntoView();
       }
     }
   }

web_src/less/_review.less

@@ -173,3 +173,11 @@ a.blob-excerpt:hover {
 .review-box > .segment {
   border: none !important;
 }
+
+.pull.files.diff [id] {
+  scroll-margin-top: 99px;
+
+  @media @mediaMdAndDown {
+    scroll-margin-top: 130px;
+  }
+}