[llvm] [llvm][IR] Add per-global code model attribute (PR #72077)

[via llvm-commits]

heiher wrote:

> @heiher The release/18.x branch will be created next week, could you mention this change in llvm's release notes?

:ok_hand:  PR: https://github.com/llvm/llvm-project/pull/78664 Thanks.

https://github.com/llvm/llvm-project/pull/72077