fixed conflicted phpdoc return values (see zendframework/zf2#6511
fixed conflicted phpdoc return values (see zendframework/zf2#6511

matwright/zend-eventmanager,codeliner/zend-eventmanager,MadCat34/zend-eventmanager,Maks3w/zend-eventmanager,ezimuel/zend-eventmanager