Implement VisitAssetDependencies for Arrays

[Glory2Antares]

Objective

• Since Vec<Handle<A>> and Vec<UntypedHandle> implement VisitAssetDependencies users might expect [Handle<A>; N] and [UntypedHandle; N] to also implement VisitAssetDependencies, but this is currently not the case.
• The #[dependency] attribute from the Asset derive macro should work with an implementation.

Solution

Implement VisitAssetDependencies for [Handle<A>; N] and [UntypedHandle; N]. The implementations are based on the corresponding ones for Vec.

Testing

A test for compatibility with the derive macros was added for [Handle<A>; N] and [UntypedHandle; N].

---

Showcase

Before:

// Can't use the Asset macro with a custom VisitAssetDependencies impl 
#[derive(TypePath)]
struct MyAsset {
    images: [Handle<Image>; 5],
}

impl VisitAssetDependencies for MyAsset {
    fn visit_dependencies(&self, visit: &mut impl FnMut(UntypedAssetId)) {
        for image in &self.images {
            visit(image.id().untyped());
        }
    }
}

impl Asset for MyAsset {}

After:

#[derive(Asset, TypePath)]
struct MyAsset {
    #[dependency]
    images: [Handle<Image>; 5],
}

[andriyDev]

Nice! Simple and straight forward!