Diagnostic args are still args if they're documented Fixes https://rust-lang.zulipchat.com/#narrow/stream/336883-i18n/topic/.60.23.5Bderive.28Diagnostic.29.5D.60.20works.20badly.20with.20docs/near/355597997 There's a lot of really strange code incongruencies between `Diagnostic` and `Subdiagnostic` derive. Perhaps those macros need some more overhaul, but I didn't really want to do it today.