Fix build when serialization is not enabled.

src/geometry/contact_generator/heightfield_shape_contact_generator.rs

@@ -162,7 +162,7 @@ fn do_generate_contacts(
                 collider2,
                 shape1: &sub_shape1,
                 shape2: collider2.shape(),
-                position1: position1,
+                position1,
                 position2: collider2.position(),
                 manifold,
                 workspace: sub_detector.workspace.as_deref_mut(),

src/geometry/shape.rs

@@ -365,6 +365,7 @@ impl Shape for Cone {
 
 #[cfg(feature = "dim3")]
 impl Shape for Rounded<Cylinder> {
+    #[cfg(feature = "serde-serialize")]
     fn as_serialize(&self) -> Option<&dyn Serialize> {
         Some(self as &dyn Serialize)
     }