Backport #22399
There was a serious regression in #21012 which broke the Show More
button on the diff page, and the show more button was also broken on the
file tree too.
This PR fixes this by resetting the pageData.diffFiles as the vue
watched value and reattachs a function to the show more button outside
of the file tree view.
Fix#22380
Signed-off-by: Andrew Thornton <art27@cantab.net>
This PR adds a filetree to the left side of the files/diff view.
Initially the filetree will not be shown and may be shown via a new
"Show file tree" button.
Showing and hiding is using the same icon as github. Folders are
collapsible. On small devices (max-width 991 PX) the file tree will be
hidden.
Close#18192
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>