False positive that xml_parser_create() can not take null as parameter.

[mdeweerd]

The php documentation confirms that 'null' is an allowed argument value to xml_parser_create, but phan reports a false positive.

<?php
// False positive: PhanTypeMismatchArgumentInternalProbablyReal Argument 1 ($encoding) is null of type null but \xml_parser_create() takes string

$dummy = xml_parser_create(null);

Phan 5.4.2
php-ast version 1.0.16
PHP version used to run Phan: 8.1.13