DOMNodeList elements are accessible through array notation

Fixes #67949
Merge branch 'pr/846' into PHP-5.6

* pr/846:
  DOMNodeList elements are accessible through array notation
Updated NEWS for #67949
Merge branch 'PHP-5.6'

Conflicts:
	ext/dom/dom_properties.h
	ext/dom/nodelist.c
	ext/dom/php_dom.c