[clang] [llvm] [clang][Inliner] Add opt-in inliner hints for lambdas and main-file functions (PR #228074)

[Nathan Corbyn via llvm-commits]

https://github.com/cofibrant commented:

This is very cool. I had a couple of minor things but otherwise makes sense to me. I definitely shouldn't be the last person to sign off on this, though.

https://github.com/llvm/llvm-project/pull/228074