minor - Fix documentation yaml examples for symfony/yaml component.
minor - Fix documentation yaml examples for symfony/yaml component.

symfony/yaml component does not handle multilines flow collections.
Use sequences instead.

Seanmcn/EasyAdminBundle,alexgt9/EasyAdminBundle,peterkokot/EasyAdminBundle,javiereguiluz/EasyAdminBundle,datagit/EasyAdminBundle,ogizanagi/EasyAdminBundle,thomasbeaujean/EasyAdminBundle,yceruto/EasyAdminBundle,seydu/EasyAdminBundle,ogizanagi/EasyAdminBundle,seydu/EasyAdminBundle,seydu/EasyAdminBundle,ogizanagi/EasyAdminBundle,npotier/EasyAdminBundle,gabiudrescu/EasyAdminBundle,gabiudrescu/EasyAdminBundle,ogizanagi/EasyAdminBundle,kamilZ/EasyAdminBundle,alexgt9/EasyAdminBundle,datagit/EasyAdminBundle,OskarStark/EasyAdminBundle,OskarStark/EasyAdminBundle,yceruto/EasyAdminBundle,thomasbeaujean/EasyAdminBundle,npotier/EasyAdminBundle,javiereguiluz/EasyAdminBundle,kamilZ/EasyAdminBundle,yceruto/EasyAdminBundle,thomasbeaujean/EasyAdminBundle,datagit/EasyAdminBundle,OskarStark/EasyAdminBundle,alexgt9/EasyAdminBundle,kamilZ/EasyAdminBundle,gabiudrescu/EasyAdminBundle