This patch renames two domains:
* `Polygon` -> `Face`
* `Corner` -> `Face Corner`
For the change from `polygon` to `face` I did a "deep rename" where I updated
all (most?) cases where we refere to the attribute domain in code as well.
The change from `corner` to `face corner` is only a ui change. I did not see
a real need to update all code the code for that. It does not seem to improve
the code, more on the contrary.
Ref T86818.
Differential Revision: https://developer.blender.org/D10803
28cf851a5c