Use method param type hints instead of PHPDoc

Since we require PHP 7.4, contravariance in param types is supported,
so we do not need to worry about subclasses that widen the param type.
It will be only breaking in the unlikely case a subclass uses a type that
contradicts the PHPDoc type annotation and does not not extend `DOMNode`.

Also fix the type annotation since some invocations pass it a `DOMText`,
an arbitrary sibling/child `DOMNode` or even `null`.

.php-cs-fixer.php

@@ -22,6 +22,7 @@ return (new PhpCsFixer\Config())
         'ordered_imports' => true,
         'php_unit_strict' => false,
         'phpdoc_order' => true,
+        'phpdoc_to_param_type' => true,
         // 'psr4' => true,
         'strict_comparison' => true,
         'strict_param' => true,

src/Readability.php

@@ -546,12 +546,8 @@ class Readability implements LoggerAwareInterface
     /**
      * Get the inner text of a node.
      * This also strips out any excess whitespace to be found.
-     *
-     * @param \DOMElement $e
-     * @param bool        $normalizeSpaces (default: true)
-     * @param bool        $flattenLines    (default: false)
      */
-    public function getInnerText($e, bool $normalizeSpaces = true, bool $flattenLines = false): string
+    public function getInnerText(?\DOMNode $e, bool $normalizeSpaces = true, bool $flattenLines = false): string
     {
         if (null === $e || !isset($e->textContent) || '' === $e->textContent) {
             return '';