Seesymfony/symfony#22619.

Some classes have been moved, so we must review the imports of the code samples:

• TheSymfony\Bundle\FrameworkBundle\DependencyInjection\Compiler\TranslationDumperPass
  class has been deprecated and will be removed in 4.0. Use the
  Symfony\Component\Translation\DependencyInjection\TranslationDumperPass class instead.

• TheSymfony\Bundle\FrameworkBundle\DependencyInjection\Compiler\TranslationExtractorPass
  class has been deprecated and will be removed in 4.0. Use the
  Symfony\Component\Translation\DependencyInjection\TranslationExtractorPass class instead.

• TheSymfony\Bundle\FrameworkBundle\DependencyInjection\Compiler\TranslatorPass
  class has been deprecated and will be removed in 4.0. Use the
  Symfony\Component\Translation\DependencyInjection\TranslatorPass class instead.