[pp-1] Explore type hinding tightening on the hook attribute

This is a code style change, fully equivalent to original code (except support for some old php versions), so it does not really tighten anything.
Changing title.

In general I am ok with this change.

I made the same suggestion at 📌 Add order parameter to FormAlter attribute Active so +1 for me. Will RTBC when the pipeline is green.

x-posted a title change, but thankfully d.o prevented that. 😅 Even more accurate title now. 😂

Pipeline is now green. Trivial change. Summary and title are clear.

Saving credit for everyone.

Even more clear summary. 😅

Committed to 11.x and pushed.
Glad I'm wasn't going mad when I questioned this during review. That issue already had me questioning my 25 years of PHP experience with its use of array_is_list and array_replace, two functions I'd never used before.

larowlan → closed merge request !12069

Thanks!