Fix minor issue in cluster groups documentation
Fix minor issue in cluster groups documentation

albertocsm/karaf-cellar,mcculls/karaf-cellar,mcculls/karaf-cellar,apache/karaf-cellar,FlavioF/karaf-cellar,albertocsm/karaf-cellar,3cky/karaf-cellar,FlavioF/karaf-cellar,3cky/karaf-cellar,3cky/karaf-cellar,apache/karaf-cellar,FlavioF/karaf-cellar,albertocsm/karaf-cellar