Fix reset to Poll after the event loop starts

src/window.rs

@@ -45,6 +45,7 @@ pub use raw_window_handle;
 /// };
 ///
 /// let mut event_loop = EventLoop::new().unwrap();
+/// event_loop.set_control_flow(ControlFlow::Wait);
 /// let window = Window::new(&event_loop).unwrap();
 ///
 /// event_loop.run(move |event, elwt| {