CREATE STATISTICS completion was checking manually for the start and end
of the parenthesised list of types. That works, but we now have a better
way to do that as commit 121213d9 taught word_matches() to allow '*' in
the middle of an alternative. But it only applied that to tab completion
for EXPLAIN, ANALYZE and VACUUM. Use it for CREATE STATISTICS too.

Author: Dagfinn Ilmari Mannsåker
Discussion: https://www.postgresql.org/message-id/flat/d8jwooziy1s.fsf%40dalvik.ping.uio.no