Derive Macro JsonPointerTarget 

#[derive(JsonPointerTarget)]
{
    // Attributes available to this derive:
    #[ploidy]
}

Derives the JsonPointerTarget trait for downcasting a type-erased JsonPointee reference to a concrete type reference.

Note that this macro generates an impl JsonPointerTarget<'a> for &'a T, not for T.

The only supported container attribute is #[ploidy(pointer(crate = "path"))] to override the crate path.