Highlighting breaks for advanced PyStringNode

[rudiedirkx]

For example Behat's own test append_snippets.feature. It has a step that creates a FeatureContext to test, and it contains ' and ":

    Given a file named "features/bootstrap/FeatureContext.php" with:
      """
      <?php

      use Behat\Behat\Context\CustomSnippetAcceptingContext,
          Behat\Behat\Tester\Exception\PendingException;
      use Behat\Gherkin\Node\PyStringNode,
          Behat\Gherkin\Node\TableNode;

      class FeatureContext implements CustomSnippetAcceptingContext
      {
          private $apples = 0;
          private $parameters;

          public static function getAcceptedSnippetType() { return 'regex'; }

          public function __construct(array $parameters = array()) {
              $this->parameters = $parameters;
          }

          /**
           * @Given /^I have (\d+) apples?$/
           */
          public function iHaveApples($count) {
              $this->apples = intval($count);
          }

          /**
           * @When /^I ate (\d+) apples?$/
           */
          public function iAteApples($count) {
              $this->apples -= intval($count);
          }

          /**
           * @When /^I found (\d+) apples?$/
           */
          public function iFoundApples($count) {
              $this->apples += intval($count);
          }

          /**
           * @Then /^I should have (\d+) apples$/
           */
          public function iShouldHaveApples($count) {
              \PHPUnit_Framework_Assert::assertEquals(intval($count), $this->apples);
          }

          /**
           * @Then /^context parameter "([^"]*)" should be equal to "([^"]*)"$/
           */
          public function contextParameterShouldBeEqualTo($key, $val) {
              \PHPUnit_Framework_Assert::assertEquals($val, $this->parameters[$key]);
          }

          /**
           * @Given /^context parameter "([^"]*)" should be array with (\d+) elements$/
           */
          public function contextParameterShouldBeArrayWithElements($key, $count) {
              \PHPUnit_Framework_Assert::assertInternalType('array', $this->parameters[$key]);
              \PHPUnit_Framework_Assert::assertEquals(2, count($this->parameters[$key]));
          }

          private function doSomethingUndefinedWith() {}
      }
      """

The highlighting breaks after the first " in the PyString. It should ignore ALL tokens inside a PyString, except the end: """.

I have no idea how to fix. Thanks for the otherwise great package!