message: Simplify pattern match in `image::Viewer::on_event`
diff: @@ -270,27 +270,22 @@ where
  }
  }
  }
  - Event::Mouse(mouse::Event::ButtonPressed(button))
  + Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
  if is_mouse_over =>
  {
  - if button == mouse::Button::Left {
  self.state.starting_cursor_pos = Some(cursor_position);
  -
  self.state.starting_offset = self.state.current_offset;
  }
  - }
  - Event::Mouse(mouse::Event::ButtonReleased(button)) => {
  - if button == mouse::Button::Left {
  + Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left)) => {
  self.state.starting_cursor_pos = None
  }
  - }
  - Event::Mouse(mouse::Event::CursorMoved { position }) => {
  - if self.state.is_cursor_clicked() {
  + Event::Mouse(mouse::Event::CursorMoved { position })
  + if self.state.is_cursor_clicked() =>
  + {
  let image_size = self.image_size(renderer, bounds.size());
  self.state.pan(position.x, position.y, bounds, image_size);
  }
  - }
  _ => {}
  }
  