[clang-tools-extra] [clang-tidy] add new check: modernize-use-scoped-lock (PR #126434)

[Congcong Cai via cfe-commits]

https://github.com/HerrCai0907 approved this pull request.

LGTM with nits
1. follow LLVM coding guideline to remove `{}` for only one lines if / for / ...
2. personal I prefer to use different function name instead of `emitDiag` for everythings.

https://github.com/llvm/llvm-project/pull/126434