[clang-tools-extra] [clang-tidy] Do not emit file path for anonymous enums in `readability-enum-initial-value` check (PR #112496)

[Donát Nagy via cfe-commits]

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

Looks good to me, this is an important improvement of report quality.

If the analysis is performed in a cloud-based environment (which is common), the full path name of the analyzed file may contain e.g. directory names that are unpredictably changing between runs, which seriously hinders comparing the results between different runs.

My only remark is that it would be more natural to use `unnamed enum` instead of the current `enum '<unnamed>'` (but this is not a blocking issue).

https://github.com/llvm/llvm-project/pull/112496