[llvm] [SeparateConstOffsetFromGEP] Highlight that trunc is handled. NFC (PR #154563)

[Fabian Ritter via llvm-commits]

https://github.com/ritter-x2a approved this pull request.

LGTM, I think this makes the code easier to follow.

https://github.com/llvm/llvm-project/pull/154563