[clang-tools-extra] [clang-tidy] Fix `cppcoreguidelines-use-enum-class` anonymous enum bug (PR #215352)

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void2012 wrote:

I did in https://github.com/llvm/llvm-project/pull/215352/changes/89e11adb8cb7a463ae2f5c460e05759c63161086, or perhaps the wording should be different? 

https://github.com/llvm/llvm-project/pull/215352