message: Simplify `pick_list` example
diff: use iced::{
  - button, pick_list, scrollable, Align, Button, Container, Element, Length,
  - PickList, Sandbox, Scrollable, Settings, Space, Text,
  + pick_list, scrollable, Align, Container, Element, Length, PickList,
  + Sandbox, Scrollable, Settings, Space, Text,
  };
  pub fn main() {
  @@ -10,14 +10,12 @@ pub fn main() {
  #[derive(Default)]
  struct Example {
  scroll: scrollable::State,
  - button: button::State,
  pick_list: pick_list::State,
  selected_language: Language,
  }
  #[derive(Debug, Clone, Copy)]
  enum Message {
  - ButtonPressed,
  LanguageSelected(Language),
  }
  @@ -34,7 +32,6 @@ impl Sandbox for Example {
  fn update(&mut self, message: Message) {
  match message {
  - Message::ButtonPressed => {}
  Message::LanguageSelected(language) => {
  self.selected_language = language;
  }
  @@ -49,20 +46,15 @@ impl Sandbox for Example {
  Message::LanguageSelected,
  );
  - let button = Button::new(&mut self.button, Text::new("Press me!"))
  - .on_press(Message::ButtonPressed);
  -
  let mut content = Scrollable::new(&mut self.scroll)
  .width(Length::Fill)
  .align_items(Align::Center)
  .spacing(10)
  - .push(Space::with_height(Length::Units(800)))
  + .push(Space::with_height(Length::Units(600)))
  .push(Text::new("Which is your favorite language?"))
  .push(pick_list);
  - content = content
  - .push(button)
  - .push(Space::with_height(Length::Units(800)));
  + content = content.push(Space::with_height(Length::Units(600)));
  Container::new(content)
  .width(Length::Fill)
  