[clang] [clang][analyzer] Add new option to specify functions `SecuritySyntaxChecker` warns about (PR #164184)

[Balazs Benics via cfe-commits]

https://github.com/steakhal requested changes to this pull request.

Hey, sorry for the long delay, but better later than never, right?

See most of my comments inline.
I have one additional note, new options should be documented in the docs alongside the rest of the checker options so that it will be present at https://clang.llvm.org/docs/analyzer/checkers.html

https://github.com/llvm/llvm-project/pull/164184