Update form_field_definition.rst
Update form_field_definition.rst

Fixed outdated documentation
rschumacher/SonataDoctrineORMAdminBundle,sonata-project/SonataDoctrineORMAdminBundle,rmzamora/SonataDoctrineORMAdminBundle,aurelien-vtech/SonataDoctrineORMAdminBundle,rmzamora/SonataDoctrineORMAdminBundle,aitboudad/SonataDoctrineORMAdminBundle,nlzet/SonataDoctrineORMAdminBundle,pulzarraider/SonataDoctrineORMAdminBundle,Bladrak/SonataDoctrineORMAdminBundle,pulzarraider/SonataDoctrineORMAdminBundle,nlzet/SonataDoctrineORMAdminBundle,rschumacher/SonataDoctrineORMAdminBundle,rschumacher/SonataDoctrineORMAdminBundle,nlzet/SonataDoctrineORMAdminBundle,pulzarraider/SonataDoctrineORMAdminBundle,aurelien-vtech/SonataDoctrineORMAdminBundle,nlzet/SonataDoctrineORMAdminBundle,rmzamora/SonataDoctrineORMAdminBundle,aurelien-vtech/SonataDoctrineORMAdminBundle,rschumacher/SonataDoctrineORMAdminBundle