Update coding style for upcoming PHP-CS-Fixer changes

Once we bump minimum PHP version, we will get newer PHP-CS-Fixer,
which will try to apply this cleanups.

(partially cherry picked from commit 648d8c605b)

Though avoid disabling `modernize_strpos` since it was only introduced in PHP-CS-Fixer 3.2.0:
https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/commit/2ca22a27c4ffb8cc46f20e7110b1dfcbb0c8c47c

Also had to disable `visibility_required` for constants since those require PHP ≥ 7.1:
https://cs.symfony.com/doc/rules/class_notation/visibility_required.html

And remove type hint from `grabArticle` since implicitly nullable types were deprecated in PHP 8.4:
https://wiki.php.net/rfc/deprecate-implicitly-nullable-types
But we cannot use explicitly nullable types, which require PHP ≥ 7.1:
https://wiki.php.net/rfc/nullable_types

Also switch code blocks to Markdown syntax to work around `phpdoc_separation`, ApiGen uses Markdown these days anyway.
(partially cherry picked from commit 9ed89bde92)

.php-cs-fixer.php

@@ -26,6 +26,10 @@ return (new PhpCsFixer\Config())
         'strict_comparison' => true,
         'strict_param' => true,
         'concat_space' => ['spacing' => 'one'],
+        // Pulled in by @Symfony, we cannot add property types until we bump PHP to ≥ 7.4
+        'no_null_property_initialization' => false,
+        // Pulled in by @Symfony with `const` but const visibility requires PHP ≥ 7.1
+        'visibility_required' => ['elements' => ['method', 'property']],
     ])
     ->setFinder($finder)
 ;

src/JSLikeHTMLElement.php

@@ -39,9 +39,9 @@ class JSLikeHTMLElement extends \DOMElement
     /**
      * Used for setting innerHTML like it's done in JavaScript:.
      *
-     * @code
+     * ```php
      * $div->innerHTML = '<h2>Chapter 2</h2><p>The story begins...</p>';
-     * @endcode
+     * ```
      */
     public function __set($name, $value)
     {
@@ -104,9 +104,9 @@ class JSLikeHTMLElement extends \DOMElement
     /**
      * Used for getting innerHTML like it's done in JavaScript:.
      *
-     * @code
+     * ```php
      * $string = $div->innerHTML;
-     * @endcode
+     * ```
      */
     public function __get($name)
     {

src/Readability.php

@@ -366,7 +366,7 @@ class Readability implements LoggerAwareInterface
             $articleLink->setAttribute('style', 'color: inherit; text-decoration: none;');
             $articleLink->setAttribute('name', 'readabilityLink-' . $linkCount);
             $footnote->setInnerHtml('<small><sup><a href="#readabilityLink-' . $linkCount . '" title="Jump to Link in Article">^</a></sup></small> ');
-            $footnoteLink->setInnerHtml(('' !== $footnoteLink->getAttribute('title') ? $footnoteLink->getAttribute('title') : $linkText));
+            $footnoteLink->setInnerHtml('' !== $footnoteLink->getAttribute('title') ? $footnoteLink->getAttribute('title') : $linkText);
             $footnoteLink->setAttribute('name', 'readabilityFootnoteLink-' . $linkCount);
             $footnote->appendChild($footnoteLink);
 
@@ -796,7 +796,7 @@ class Readability implements LoggerAwareInterface
      */
     public function addFlag($flag)
     {
-        $this->flags = $this->flags | $flag;
+        $this->flags |= $flag;
     }
 
     /**
@@ -806,13 +806,14 @@ class Readability implements LoggerAwareInterface
      */
     public function removeFlag($flag)
     {
-        $this->flags = $this->flags & ~$flag;
+        $this->flags &= ~$flag;
     }
 
     /**
      * Debug.
      *
      * @deprecated use $this->logger->debug() instead
+     *
      * @codeCoverageIgnore
      */
     protected function dbg($msg)
@@ -824,6 +825,7 @@ class Readability implements LoggerAwareInterface
      * Dump debug info.
      *
      * @deprecated since Monolog gather log, we don't need it
+     *
      * @codeCoverageIgnore
      */
     protected function dump_dbg()
@@ -973,11 +975,11 @@ class Readability implements LoggerAwareInterface
      * Using a variety of metrics (content score, classname, element types), find the content that is
      * most likely to be the stuff a user wants to read. Then return it wrapped up in a div.
      *
-     * @param \DOMElement $page
+     * @param ?\DOMElement $page
      *
      * @return \DOMElement|false
      */
-    protected function grabArticle(\DOMElement $page = null)
+    protected function grabArticle($page = null)
     {
         if (!$page) {
             $page = $this->dom;
@@ -992,7 +994,7 @@ class Readability implements LoggerAwareInterface
 
         $allElements = $page->getElementsByTagName('*');
 
-        for ($nodeIndex = 0; ($node = $allElements->item($nodeIndex)); ++$nodeIndex) {
+        for ($nodeIndex = 0; $node = $allElements->item($nodeIndex); ++$nodeIndex) {
             $tagName = $node->tagName;
 
             $nodeContent = $node->getInnerHTML();
@@ -1136,9 +1138,9 @@ class Readability implements LoggerAwareInterface
                 // Remove unlikely candidates
                 $unlikelyMatchString = $node->getAttribute('class') . ' ' . $node->getAttribute('id') . ' ' . $node->getAttribute('style');
 
-                if (mb_strlen($unlikelyMatchString) > 3 && // don't process "empty" strings
+                if (mb_strlen($unlikelyMatchString) > 3 // don't process "empty" strings
-                    preg_match($this->regexps['unlikelyCandidates'], $unlikelyMatchString) &&
+                    && preg_match($this->regexps['unlikelyCandidates'], $unlikelyMatchString)
-                    !preg_match($this->regexps['okMaybeItsACandidate'], $unlikelyMatchString)
+                    && !preg_match($this->regexps['okMaybeItsACandidate'], $unlikelyMatchString)
                 ) {
                     $this->logger->debug('Removing unlikely candidate (using conf) ' . $node->getNodePath() . ' by "' . $unlikelyMatchString . '" with readability ' . ($node->hasAttribute('readability') ? (int) $node->getAttributeNode('readability')->value : 0));
                     $node->parentNode->removeChild($node);