Fix default value

Author: cmb69

ext/xml/xml.stub.php

@@ -4,7 +4,7 @@
 function xml_parser_create(string $encoding = UNKNOWN) {}
 
 /** @return XmlParser|false */
-function xml_parser_create_ns(string $encoding = UNBEKANNT, string $sep = ':') {}
+function xml_parser_create_ns(string $encoding = UNKNOWN, string $sep = ':') {}
 
 function xml_set_object(XmlParser $parser, object $obj): bool {}