Follow up of b2ee1770d4c3 and 10c2254d412d, part of T74432.
Now the area and region naming conventions should be less confusing.
Mostly a careful batch rename but had to do few smaller fixes.
Also ran clang-format on affected files.
editors
The redo panel does not consider the position of the mouse.
So it is not possible to know the direction to redo the operator.
The solution is to add a new `direction` parameter that can be
saved and used for redo.
Differential Revision: https://developer.blender.org/D6852
