Make ZeroOrMore take Iterator instead of AsRef<[T]>

[khyperia]

This is useful if the user has an iterator instead of a slice/vec, it
saves an allocation.

I think this is a breaking change due to ref differences, not sure if we're okay with that.

(For review, the only file changed is dr.rs, the rest are generated)

[Jasper-Bekkers]

I don't quite know what we rspirv typically does with breaking changes - nor do I know if the change from AsRef<[T]> to IntoIterator is a breaking change.

However, I'm inclined to accept it because this crate is already a bit on the alloc-heavy side of things, so getting that down would be quite nice.

[kvark]

Looks like a breaking change to me, given that AsRef<[T]> would be implemented for &[T] but IntoIterator<T> wouldn't.

[Jasper-Bekkers]

Might be good to merge this in after #143