[clang] [Clang] Added explanation why a is trivial copyable evaluated to false. (PR #142341)

[Corentin Jabot via cfe-commits]

https://github.com/cor3ntin approved this pull request.

LGTM!
Thanks a lot.
Will you need us to merge that for you?

https://github.com/llvm/llvm-project/pull/142341