rustdoc: Replace all remaining uses of `Type::def_id_no_primitives()` with `Type::def_id()`

[camelid]

Steps

1. Pass &Cache where it will be needed for def_id().
2. Replace all uses of def_id_no_primitives() with def_id().
3. Remove def_id_no_primitives() and simplify Type::inner_def_id().

[jyn514]

This is no longer blocked :)

[mfrw]

@rustbot claim