Fix method documentation to reflect recent changes
Fix method documentation to reflect recent changes

\Slim\App is not a instance of \Pimple\Container since commit https://github.com/slimphp/Slim/commit/ea4f1fc
AndrewCarterUK/Slim,mnapoli/Slim,designermonkey/Slim,iinux/Slim,slimphp/Slim,feryardiant/slim,jaapverloop/Slim,samsonasik/Slim,JoeBengalen/Slim,somjit2514/basic,akrabat/Slim,iinux/Slim,opengeek/Slim,foxyantho/Slim,iinux/Slim,juliangut/Slim,dopesong/Slim,Sam-Burns/Slim,RealSelf/Slim