Document su-gitlogcheck hook in CONTRIBUTING.md
Document su-gitlogcheck hook in CONTRIBUTING.md

crbb/sulong,lxp/sulong,grimmerm/sulong,PrinzKatharina/sulong,crbb/sulong,lxp/sulong,crbb/sulong,PrinzKatharina/sulong,grimmerm/sulong,crbb/sulong,lxp/sulong,PrinzKatharina/sulong,lxp/sulong,grimmerm/sulong,PrinzKatharina/sulong,grimmerm/sulong