[10.5.x] Add BC stubs for Hook ordering.

The constants PREFIX and SUFFIX are not released yet, they may be removed in 📌 Rethink #[Hook] attribute inheritance Active , and they are not needed to make this BC support work.

Let's limit this change to what is necessary, and also apply that correction in 11.1.x.

Also the FormAlter is not released yet, and there is no reason to add it in 10.5.x or 11.1.x.
What I remember from earlier discussions is that missing attributes are not going to cause problems, only existing attributes with incompatible signature. Or do I remember it wrong?

Also RemoveHook, ReorderHook etc don't need to be added here, I think.

Follow-up here: 📌 Reduce hook attribute order BC stubs to the minimum necessary Active

Is this safe to close now?