implemented markdown parsing for console command description
implemented markdown parsing for console command description

issue #746

yiijan/yii2-twig,andrew-kamenchuk/yii2-twig,andrew-kamenchuk/yii2-twig,yiisoft/yii2-twig,quantum13/yii2-twig,pana1990/yii2-twig,yiijan/yii2-twig,quantum13/yii2-twig,pana1990/yii2-twig