derive(AsRef) with generic boundaries is not compiling

[greyblake]

The following should work:

#[nutype(
    sanitize(with = |mut v| { v.sort(); v }),
    validate(predicate = |vec| !vec.is_empty()),
    derive(Debug, PartialEq, AsRef),
)]
struct SortedNotEmptyVec<T: Ord>(Vec<T>);

[greyblake]

Fixed in #158