Fix mysqli_get_client_info() stub

The dummy link argument is not nullable.

Author: nikic

ext/mysqli/mysqli.stub.php

@@ -360,7 +360,7 @@ function mysqli_get_client_stats(): array {}
 
 function mysqli_get_charset(mysqli $mysqli_link): ?object {}
 
-function mysqli_get_client_info(?mysqli $mysqli_link = null): ?string {}
+function mysqli_get_client_info(mysqli $mysqli_link = UNKNOWN): ?string {}
 
 function mysqli_get_client_version(): int {}
 

ext/mysqli/mysqli_arginfo.h

@@ -144,7 +144,7 @@ ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_mysqli_get_charset, 0, 1, IS_OBJ
 ZEND_END_ARG_INFO()
 
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_mysqli_get_client_info, 0, 0, IS_STRING, 1)
-	ZEND_ARG_OBJ_INFO_WITH_DEFAULT_VALUE(0, mysqli_link, mysqli, 1, "null")
+	ZEND_ARG_OBJ_INFO(0, mysqli_link, mysqli, 0)
 ZEND_END_ARG_INFO()
 
 #define arginfo_mysqli_get_client_version arginfo_mysqli_connect_errno