[clang-tools-extra] [clang-tidy] Add documentation and smoke test for CUDA (PR #173699)

[Carlos Galvez via cfe-commits]

================

----------------
carlosgalvezp wrote:

Rename to `Inputs/cuda.h` for consistency with other parts of the repo.

There's several copies in the repo, I don't think it's a problem to add one more or that special credit is needed.

https://github.com/llvm/llvm-project/pull/173699