[llvm-branch-commits] [CIR] Add .clang-tidy files to agree with our style convention (PR #108444)

[Nathan Lanza via llvm-branch-commits]

https://github.com/lanza created https://github.com/llvm/llvm-project/pull/108444

https://llvm.github.io/clangir/GettingStarted/coding-guideline.html