Fix tests

Author: ondrejmirtes

tests/PHPStan/Analyser/data/bug-8072.php

@@ -8,13 +8,13 @@ function say(\Closure $bar): string
 }
 
 function (): void {
-	echo say(fn (string $name = null) => 'Hi');
-	echo say((fn (string $name = null) => 'Hi')(...));
+	echo say(fn (?string $name = null) => 'Hi');
+	echo say((fn (?string $name = null) => 'Hi')(...));
 
-	echo say(function (string $name = null) {
+	echo say(function (?string $name = null) {
 		return 'Hi';
 	});
-	echo say((function (string $name = null) {
+	echo say((function (?string $name = null) {
 		return 'Hi';
 	})(...));
 };