Merge branch '24641-focus-state' into 'master'

Fix focus state in preview tab

## What does this MR do?
Fixes the focus border in the preview tab by modifying the `line-height`, keeping the same height 🤸 

## Screenshots (if relevant)
![Screen_Shot_2016-11-18_at_18.35.36](/uploads/3ef96699194704f030cc8d2b5132226c/Screen_Shot_2016-11-18_at_18.35.36.png)

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
Closes #24641

See merge request !7581

app/assets/stylesheets/framework/markdown_area.scss

@@ -64,12 +64,17 @@
 
     a {
       padding-top: 0;
-      line-height: 1;
+      line-height: 19px;
       border-bottom: 1px solid $border-color;
 
       &.btn.btn-xs {
         padding: 2px 5px;
       }
+
+      &:focus {
+        margin-top: -10px;
+        padding-top: 10px;
+      }
     }
   }
 }