[clang-tools-extra] [clang-tidy] Compact the confusable identifier table (PR #202626)

[Zeyi Xu via cfe-commits]

https://github.com/zeyi2 approved this pull request.

LGTM with some small nits. clang-tidy codebase already commonly relies on transitive includes for standard headers, LLVM's coding standard also [suggests include as little as possible](https://llvm.org/docs/CodingStandards.html#include-as-little-as-possible). Would you please remove these redundant headers? Please see the inline comments below.

https://github.com/llvm/llvm-project/pull/202626