[clang-tools-extra] [clang-tidy] fix cppcoreguidelines-narrowing-conversions false positives when narrowing integer to signed integer in C++20 (PR #116591)

[Congcong Cai via cfe-commits]

HerrCai0907 wrote:

Maybe we should move this check to bugprone and use some configuration to enforce guideline in cppcoreguidelines parts. WDYT? @carlosgalvezp @PiotrZSL

https://github.com/llvm/llvm-project/pull/116591