[clang-tools-extra] [clang-tidy] Added check 'bugprone-function-visibility-change' (PR #140086)

[Balázs Kéri via cfe-commits]

balazske wrote:

> > In my opinion, it should not be bugprone because I don't find any potential bug in this code style. Maybe it more like a readability issue? @PiotrZSL @EugeneZelenko what do you think?
> 
> Sorry, I don't have strong opinion on this matter.

I think the "misc" module would be the best place for this check.

https://github.com/llvm/llvm-project/pull/140086