code: protected function applyFix(\SplFileInfo $file, Tokens $tokens)
      {
          $lineEnding = $this->whitespacesConfig->getLineEnding();
  
          // ignore files with short open tag and ignore non-monolithic files
          if (!$tokens[0]->isGivenKind(T_OPEN_TAG) || !$tokens->isMonolithicPhp()) {
              return;
          }
  
          $newlineFound = false;
          /** @var Token $token */
          foreach ($tokens as $token) {
              if ($token->isWhitespace() && false !== strpos($token->getContent(), "\n")) {
                  $newlineFound = true;
  
                  break;
              }
          }
  
          // ignore one-line files
          if (!$newlineFound) {
              return;
          }
  
          $token = $tokens[0];
  
          if (false === strpos($token->getContent(), "\n")) {
              $tokens[0] = new Token([$token->getId(), rtrim($token->getContent()).$lineEnding]);
          }
  
          if (!$tokens[1]->isWhitespace() && false === strpos($tokens[1]->getContent(), "\n")) {
              $tokens->insertAt(1, new Token([T_WHITESPACE, $lineEnding]));
          }
      }
docs: {@inheritdoc}