fix bug in ibitset find_next method (#338)
fix bug in ibitset find_next method (#338)

Co-authored-by: John Wellbelove <3452b466aac1026c4531447267fa2124aca89399@users.noreply.github.com>
ETLCPP/etl,ETLCPP/etl,ETLCPP/etl,ETLCPP/etl