[clang-tools-extra] [clang-tidy] Add a fully custom message to `bugprone-unsafe-functions` (PR #162443)

[Donát Nagy via cfe-commits]

https://github.com/NagyDonat commented:

Overall looks good to me.

Why did you select the prefix `>` for activating this feature? (It's perfectly acceptable, I'm just curious.) 

I feel that it may be a bit confusing that in the comments / release notes etc.   "replacement message" may also refer to the `it should not be used` suffix of the message. Maybe "default message suffix" or something similar would be less ambiguous.

https://github.com/llvm/llvm-project/pull/162443