Focus textbox when opening the branch selector when creating a new MR
Description
When opening the branch selector in the new merge request view, the textbox for selecting the branch isn't automatically selected.
Proposal
The textbox should automatically be selected.
Links / references
Mentioned on HN: https://news.ycombinator.com/item?id=14617611
Use Cases
This makes UX a bit faster, because, not, it requires one click instead of two.