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

[Baranov Victor via cfe-commits]

https://github.com/vbvictor commented:

With new patchers, main page of `clang-tidy` more looks like a wall of text and personally It's a little scary to read. Maybe we could refactor it later for smaller pieces, but that is for another issue.

Left one minor comment.

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