editor: Fix diff hunk controls not shown until buffer interaction (#32692)

Similar to https://github.com/zed-industries/zed/pull/32683, checking
mouse hovered in `mouse_move` instead of `prepaint` for diff hunk
controls.

Release Notes:

- Fixed issue where diff hunk controls were not visible on mouse hover
when `cursor_blink` is `false`.
2aa79a022eSmit Barmase committed on 6/13/2025, 4:59:49 PM· committed by GitHubparent71dbe88
2 files changedLine totals unavailable