NonUniqueResourceId

[stepancheg]

Follow-up to https://github.com/bevyengine/bevy/pull/10793

Rendered

struct NonUniqueResourceId<T> { /* ... */ }

impl<T> NonUniqueResourceId<T> {
    fn new() -> Self { /* ... */ }
}

impl NonUniqueResourceId<T> {
    fn write_system(&self) -> impl System<In=T, Out=()> { /* ... */ }
    
    fn read_system(&self) -> impl System<(), Out=()> { /* ... */ }
}