Fix rust-analyzer error in example bounding 2d

[jiangheng90]

Objective

the rust-analyzer error in example bounding 2d

fn render_shapes(mut gizmos: Gizmos, query: Query<(&Shape, &Transform)>) {
    let color = GRAY;
    for (shape, transform) in query.iter() {
        let translation = transform.translation.xy();
        let rotation = transform.rotation.to_euler(EulerRot::YXZ).2;
        let isometry = Isometry2d::new(translation, Rot2::radians(rotation));
        match shape {
            Shape::Rectangle(r) => {
                gizmos.primitive_2d(r, isometry, color);
            }

the r will cause expected &{unknown}, found Rectangle

Solution

this error will occure in many place in this example
for match adding ref will solve this and pass lint