This makes one change and another correction to the mouse cursors used
during Docking. The change is to use WM_CURSOR_EDIT for Mac while just
hovering over the corner action zones. This means that Mac users will
transition from this to WM_CURSOR_HAND_CLOSED, instead using two hand
cursors. The correction is to use the "split" cursors while splitting
areas. That it doesn't do that now is a mistake made during #127810.
Pull Request: https://projects.blender.org/blender/blender/pulls/128396
bfe693c8c2