[McP]

Nice to see ignore-revs getting some love :)

I originally wrote it because I wanted to do a mass-refactoring to llvm-project to change its weird naming convention and "it will mess up git blame" was an objection that was raised. Getting ignore-revs landed took many iterations over several months (thanks Barret!) and at the end of it I felt so drained that I didn't have the energy to do the mass refactoring I originally planned. Oh well. Maybe someday.

[mabster]

A big thank you! Blame history being correct is something i care quite a bit about and I always add one of these files when I do formatting changes. I think I'm probably the only developer on my teams with this configured on though haha!