Consider renaming AggregateUDFImpl::is_ordered_set_aggregate to AggregateUDFImpl::supports_within_group_clause #18280
Description
Is your feature request related to a problem or challenge?
See #17805 (comment)
Describe the solution you'd like
No response
Describe alternatives you've considered
No response
Additional context
Could make hypothetical-set aggregate functions easier in future: https://www.postgresql.org/docs/9.4/functions-aggregate.html#FUNCTIONS-HYPOTHETICAL-TABLE