Description:
------------
---
From manual page: https://php.net/class.domnode
---

`DOMNode` has several properties that can be `NULL`:

* nodeValue
* parentNode
* firstChild
* lastChild
* previousSibling
* nextSibling
* attributes
* ownerDocument

The class synopsis, however, doesn't provide this important information.

Expected result:
----------------
public ?string $nodeValue ;
public readonly int $nodeType ;
public readonly ?DOMNode $parentNode ;
public readonly DOMNodeList $childNodes ;
public readonly ?DOMNode $firstChild ;
public readonly ?DOMNode $lastChild ;
public readonly ?DOMNode $previousSibling ;
public readonly ?DOMNode $nextSibling ;
public readonly ?DOMNamedNodeMap $attributes ;
public readonly ?DOMDocument $ownerDocument ;

Actual result:
--------------
public string $nodeValue ;
public readonly int $nodeType ;
public readonly DOMNode $parentNode ;
public readonly DOMNodeList $childNodes ;
public readonly DOMNode $firstChild ;
public readonly DOMNode $lastChild ;
public readonly DOMNode $previousSibling ;
public readonly DOMNode $nextSibling ;
public readonly DOMNamedNodeMap $attributes ;
public readonly DOMDocument $ownerDocument ;