See available Symfony rules
composer require rector/rector-symfony --dev
To add a set to your config, use Rector\Symfony\Set\SymfonySetList
class and pick one of constants:
use Rector\Symfony\Set\SymfonySetList;
use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
return static function (ContainerConfigurator $containerConfigurator): void {
$containerConfigurator->import(SymfonySetList::SYMFONY_44);
};