Previously the useEvent check in RulesOfHooks would collect all
definitions of useEvent functions at the top level, record them as
violations, then clear those violations if the useEvent function was
later called or referened inside of an effect or another event.

The flaw with this approach was in the special case where useEvent
functions could be passed by reference inside of effects or events. The
violation would be cleared here (since it was called at least once)
and subsequent usages of the useEvent function would not be properly
checked.

This PR changes it so we check all identifiers that resolve to a
useEvent function, and if they are not in an effect or event must be
called or a lint error is emitted.

Co-authored-by: Dan Abramov <[email protected]>