[clang-tools-extra] [clang-tidy] Switch misc-confusable-identifiers check to a faster algorithm. (PR #130369)

[Julian Schmidt via cfe-commits]

https://github.com/5chmidti approved this pull request.

LGTM. Thanks for the quite big performance improvement, and sorry this took a bit until it was reviewed.

https://github.com/llvm/llvm-project/pull/130369