title: Undefined type 'Symfony\Component\Form\AbstractType' and 'Symfony\Component\Form\FormBuilderInterface' also OptionsResolver is undefined
body: <p>I have generated a project as skeleton and installed Form using <code>composer require form</code> and I generated using <code>php bin/console make:form</code> but it is showing undefined for all AbstractType, FormBuilderInterface and OptionsResolver.</p>
  <pre class="lang-php prettyprint-override"><code>&lt;?php
  
  namespace App\Form;
  
  use App\Entity\User;
  use Symfony\Component\Form\AbstractType;
  use Symfony\Component\Form\FormBuilderInterface;
  use Symfony\Component\OptionsResolver\OptionsResolver;
  
  class UserType extends AbstractType
  {
      public function buildForm(FormBuilderInterface $builder, array $options)
      {
          $builder
              -&gt;add('name')
              -&gt;add('email')
              -&gt;add('mobile')
          ;
      }
  
      public function configureOptions(OptionsResolver $resolver)
      {
          $resolver-&gt;setDefaults([
              'data_class' =&gt; User::class,
          ]);
      }
  }
  </code></pre>