Matching osu!stable. I use these quite a lot while mapping and I'm sure
others do as well.
Hold `Shift` = invert grid snap
Hold `Alt` = invert distance snap
Closes https://github.com/ppy/osu/issues/20824.
Note that this will require a reimport of beatmaps as it is baked into the database. Probably not worth making a migration for at this point in time.