[clang] [clang][dataflow] `bugprone-unchecked-optional-access`: Add support for std::exchange. (PR #227526)

[Jan Voung via cfe-commits]

https://github.com/jvoung approved this pull request.

Thank you! One nit, otherwise LG

I was wondering if this could be part of the builtin transfer, but not sure that will be able to handle the specific domain's implicit conversion (T, U) template params (similar to operator=).

https://github.com/llvm/llvm-project/pull/227526