[clang] [clang] Revise relnote for int->enum conversion. (PR #145755)

[Erich Keane via cfe-commits]

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

Definitely better, and probably good enough.  I find myself wondering whether we we want to say `it was fixed in Boost 1.81 in commits<a/b/c>` to help people know if they want to cherry-pick those.  WDYT?

https://github.com/llvm/llvm-project/pull/145755