Fix a couple of lints

src/widgets/machines.rs

@@ -87,7 +87,7 @@ impl RotatingMachine {
           Pickable::default(),
         ))
         .with_children(|cmds| {
-          let button_cmds = cmds.spawn(BigRedButton::bundle("TURN"));
+          let _button_cmds = cmds.spawn(BigRedButton::bundle("TURN"));
           // TODO: Attach on-press observer to the button.
         });
     });