readme clarification

Author: Rct567

README.md

@@ -100,7 +100,7 @@ DomQuery::create('<a title="hello"></a>')->attr('title') // hello
 
 ## XML support
 
-- XML content will automatically be loaded '[as XML](http://php.net/manual/en/domdocument.loadxml.php)'
+- XML content will automatically be loaded '[as XML](http://php.net/manual/en/domdocument.loadxml.php)' if a XML declaration is found
 - Namespaces should be automatically registered (no need to do it [manually](http://php.net/manual/en/domxpath.registernamespace.php))
 
 Escaping meta chars in selector to find elements with namespace: