[clang] [docs] update noescape semantics to disallow free (PR #195973)

[Aaron Ballman via cfe-commits]

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

LGTM, thank you! Will there be a follow-up to change lowering to `captures(address)`?

https://github.com/llvm/llvm-project/pull/195973