Sync datefmt_get_calendar_object signature

In this case, it's only a matter of using the same type order
in both cases.

Author: nikic

ext/intl/dateformat/dateformat.stub.php

@@ -48,7 +48,7 @@ public function setCalendar(IntlCalendar|int|null $calendar) {}
     public function getTimeZoneId() {}
 
     /**
-     * @return IntlCalendar|null|false
+     * @return IntlCalendar|false|null
      * @alias datefmt_get_calendar_object
      */
     public function getCalendarObject() {}

ext/intl/dateformat/dateformat_arginfo.h

@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: 437726f2d61a93d530e7e3b6df0741ae68c64697 */
+ * Stub hash: 62742b5f463272f43970e98900a89d513c4fb839 */
 
 ZEND_BEGIN_ARG_INFO_EX(arginfo_class_IntlDateFormatter___construct, 0, 0, 3)
 	ZEND_ARG_TYPE_INFO(0, locale, IS_STRING, 1)