code: public function process(Tokens $tokens, Token $token, $index)
      {
          if (!$token->equals('?')) {
              return;
          }
  
          $prevIndex = $tokens->getPrevMeaningfulToken($index);
          $prevToken = $tokens[$prevIndex];
  
          if ($prevToken->equalsAny(['(', ',', [CT::T_TYPE_COLON]])) {
              $tokens[$index] = new Token([CT::T_NULLABLE_TYPE, '?']);
          }
      }
docs: {@inheritdoc}