Reattach the close button to the rotator machine

That was much easier than I expected it to be. I'm still going to alter
how the `machine_ui_base` function works so that I don't have to
remember to attach a button all the time.

src/widgets/machines.rs

@@ -2,7 +2,7 @@ use bevy::{color::palettes::css::*, prelude::*, ui::Val::*};
 
 use crate::{
   game::machines::*,
-  widgets::{machine_ui_base, spawn_big_red_button},
+  widgets::{CloseButton, machine_ui_base, spawn_big_red_button},
 };
 
 impl CuttingMachine {
@@ -52,6 +52,7 @@ impl RotatingMachine {
     commands
       .spawn((machine_ui_base("Rotating Machine"),))
       .with_children(|commands| {
+        commands.spawn(CloseButton::bundle(commands.target_entity()));
         commands.spawn((
           Node {
             padding: UiRect::all(Px(10.0)),