The main simplification is using return values rather than return
arguments, and the additional semantic clarity from std::optional.
Also use `fmt` for formatting and use lambdas instead of macros
as helpers in a few modal keymap formatting functions.
Similar commits:
- a1792e98a4
- f04bc75f8c
- 6abf43cef5
- 7ca4dcac5a
Pull Request: https://projects.blender.org/blender/blender/pulls/117785