Update core.stub

Author: staabm

stubs/core.stub

@@ -357,3 +357,8 @@ function register_shutdown_function(callable $callback, mixed ...$args): void {}
  * @param-later-invoked-callable $callback
  */
 function header_register_callback(callable $callback): bool {}
+
+/**
+ * @param-later-invoked-callable $callback
+ */
+function register_tick_function(callable $callback, mixed ...$args): bool {}