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

[Shafik Yaghmour via cfe-commits]

https://github.com/shafik commented:

Thank you for the fix. 

Please add more details to your summary, explaining why the motivation for the fix and some details on how it is being implemented. 

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