[llvm] [flang] [libc] [libcxx] [clang] [clang-tools-extra] [compiler-rt] [libc++] Implement LWG3940: std::expected<void, E>::value() also needs E to be copy constructible (PR #71819)

[Mark de Wever via cfe-commits]

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

> LGTM. @mordante could you please have another look if the current state addressed your concerns?

Yes looks fine to me.

https://github.com/llvm/llvm-project/pull/71819