Fix and deprecate unusual uses of st.recursive()

[Zac-HD]

Closes #4638

[Liam-DeVoe]

Noting that there are (very contrived, surely) ways to defeat is_first_param_referenced_in_function:

>>> from hypothesis import strategies as st
>>> st.recursive(st.none(), lambda x: st.lists(locals()['x'])).example()
/Users/tybug/Desktop/Liam/coding/hypothesis/hypothesis-python/src/hypothesis/strategies/_internal/strategies.py:508: HypothesisDeprecationWarning: extend=lambda x: <unknown> doesn't use it's argument, and thus can't actually recurse!
  self.do_validate()
[[None], [None, None, None, None, None, None, None, None, None], [], None]
>>> 

which means I'd lean towards making this a warning, which can be suppressed if we get it wrong, rather than an error after the deprecation period.

(Same applies for the draw-not-used warning for @st.composite).

[Zac-HD]

"don't do that, then"

[Liam-DeVoe]

sure, but users will be rightfully annoyed that we presume to know better than them and they can't silence our opinions :)

To be clear I don't view this as blocking. I figured we'd disagree on this; and I still wanted to put my opinion on record here

[Liam-DeVoe]

unknown might be more clear than ?, but I'll wait to see this in action to form a solid opinion