[libcxx-commits] [libcxx] [libc++] mark `std::expected` as `nodiscard` (PR #130820)

[via libcxx-commits]

R-Goc wrote:

I also feel like implicitly ignoring an expected is always a bug. It would be nice to see a reason added to it. 

https://github.com/llvm/llvm-project/pull/130820