Support PHP8 Attributes

[tacman]

All the cool kids are using attributes instead of annotations...

I'll submit a PR in a bit, so we can do:

    #[Feature(name: "abc")]
    #[Route('/demo', name: 'app_demo')]
    public function demo(): Response
    {
        return $this->render('app/index.html.twig', [
        ]);
    }