feat: auto close buffer opened by diff_view

[D7ry]

By setting delete_buffer_on_diff_exit in config, diff_view automatically closes all buffers opened as a result of previewing diff. I found myself checking the diffs a lot, that ends up adding a lot of buffers that clutters up my buffer line.

Buffers that are already opened before opening diff view aren't affected.

[MrRoiz]

Any update on this? I'd love this feature.