Fix extracting identifiers

Author: ondrejmirtes

src/Rules/RestrictedUsage/RestrictedMethodCallableUsageRule.php

@@ -43,6 +43,7 @@ public function processNode(Node $node, Scope $scope): array
 			return [];
 		}
 
+		/** @var RestrictedMethodUsageExtension[] $extensions */
 		$extensions = $this->extensions ??= $this->container->getServicesByTag(RestrictedMethodUsageExtension::METHOD_EXTENSION_TAG);
 		if ($extensions === []) {
 			return [];