/**
* @param string $errorMessage Localisation message describing the error (since MW 1.26)
- * @param string $titleText The invalid title text (since MW 1.26)
+ * @param string|null $titleText The invalid title text (since MW 1.26)
* @param string[] $errorMessageParameters Additional parameters for the error message.
* $titleText will be appended if it's not null. (since MW 1.26)
*/