[clang] clang: Add pragma clang fp reciprocal (PR #68267)

[Zahira Ammarguellat via cfe-commits]

zahiraam wrote:

Can you please fix the description of the patch.
Please note that Melanie has retired. You can add me as a reviewer for all FP related work. Thanks.

https://github.com/llvm/llvm-project/pull/68267