[clang-tools-extra] [Clang-Tidy][NFC] Simplify check cppcoreguidelines-missing-std-forward (PR #138504)

[Carlos Galvez via cfe-commits]

carlosgalvezp wrote:

> because the cases handled by it are covered by CaptureByRefExplicit.

Strange, can you explain why that's the case? Are we missing tests?

https://github.com/llvm/llvm-project/pull/138504