Display "base" label in versions drop down
What does this MR do?
Relates to: #27008 (closed)
Displays "(head)" label in compare versions drop-down when viewing the "diff_head=true" query string
To test simply open any merge request and go to the changes tab. Then add "diff_head=true" as a querystring to the url i.e. http://localhost:3000/h5bp/html5-boilerplate/-/merge_requests/1/diffs?diff_head=true