[clang] [clang-tools-extra] [clang-tidy] Add support for bsl::optional (PR #101450)

[Chris Cotter via cfe-commits]

ccotter wrote:

Agreed it should be configurable.

I updated the docs, would you mind merging if you are OK as I don't have perms?

https://github.com/llvm/llvm-project/pull/101450