title: Symfony doctrine migration fails when using custom mapping type
body: <p>I try to introduce a custom mapping type but it fails in the following way:</p>
  <pre><code>1064 You have an error in your SQL syntax; check the manual that corresponds 
  to your MySQL server version for the right syntax to use near 
  'localizedstring NOT NULL COMMENT '(DC2Type:localizedstring)', 
  PRIMARY KEY(id)) D' at line 1
  </code></pre>
  <p>This is my type class:</p>
  <pre><code>namespace App\Orm\Custom\MappingTypes;
  
  [...]
  
  use Doctrine\DBAL\Platforms\AbstractPlatform;
  use Doctrine\DBAL\Types\Type;
  
  [...]
  
  class LocalizedStringType extends Type
  {
      const LOCALIZED_STRING = 'localizedstring';
  
      public function requiresSQLCommentHint(AbstractPlatform $platform): bool
      {
          return true;
      }
  
      public function convertToDatabaseValue($value, AbstractPlatform $platform)
      {
         [...]
      }
  
      public function convertToPHPValue($value, AbstractPlatform $platform)
      {
         [...]
      }
  
      public function getSQLDeclaration(array $column, AbstractPlatform $platform): string
      {
          return 'localizedstring';
      }
  
      public function getName(): string
      {
          return self::LOCALIZED_STRING;
      }
  }
  </code></pre>
  <p>This my doctrine.yaml:</p>
  <pre><code>doctrine:
      dbal:
          url: '%env(resolve:DATABASE_URL)%'
          types:
              localizedstring: App\Orm\Custom\MappingTypes\LocalizedStringType
  
      orm:
          auto_generate_proxy_classes: true
          naming_strategy: doctrine.orm.naming_strategy.underscore_number_aware
          auto_mapping: true
          mappings:
              App:
                  is_bundle: false
                  type: annotation
                  dir: '%kernel.project_dir%/src/Entity'
                  prefix: 'App\Entity'
                  alias: App
  </code></pre>
  <p>I am using:</p>
  <ul>
  <li><em>Symfony 5.1</em></li>
  <li><em>Doctrine 2.7.3</em></li>
  </ul>
  <p>Any hints are appreciated. If more information is needed, I will gladly provide it.</p>