[clang-tools-extra] [clang-tidy] New bugprone-unsafe-format-string check (PR #168691)

[Yanzuo Liu via cfe-commits]

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zwuis wrote:

Move things in this file to `clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/std` then `#include <new_header>` and remove `-isystem` in other test files.

https://github.com/llvm/llvm-project/pull/168691