No completion for enum variants through type alias

[flodiebold]

enum Enum {
    VariantA,
    VariantB
}

type Type = Enum;

fn main() {
    let x = Type::<|>;
}

We should get completions for the variants, but currently don't. Very annoying in hir_ty currently, since we have so many type aliases for Chalk enums there 😅 Type inference works otherwise for e.g. Type::VariantA, so this seems to be a completion problem (well, the actual problem is that a lot of this name resolution logic happens inside of type inference and can't be reused by completion right now).