[clang] [clang][analyzer] Move checker alpha.security.cert.pos.34c into security.PutenvWithAuto (PR #92424)

[Donát Nagy via cfe-commits]

https://github.com/NagyDonat commented:

Thanks for bringing this checker out of alpha! I like the new name and I agree that the old `Limitations` section was incorrect; and I have some minor suggestions in inline comments.

I'd also ask for running this checker on some open source projects; but as `putenv` is an outdated function, I'd guess that there would be no results.

https://github.com/llvm/llvm-project/pull/92424