in the same spirit of 724a6e26, format_as() is defined for
cql3::cql3_type. despite that this is not used yet by fmt v9,
where we still have FMT_DEPRECATED_OSTREAM, this prepares us for
fmt v10.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#16232