[libc] [llvm] [libc][math][c23] Add fsqrtf16 C23 math functions. (PR #131153)

[via llvm-commits]

https://github.com/lntue commented:

The function with `float16` input and `float16` output should be named `sqrtf16`, not `fsqrtf16`.

https://github.com/llvm/llvm-project/pull/131153