ksys: Move CollisionMasks out of RigidBody so it can be forward declared

src/KingSystem/Physics/RigidBody/physRigidBody.h

@@ -38,18 +38,20 @@ public:
     virtual ~RigidBase() = default;
 };
 
+struct RigidBodyCollisionMasks {
+    /// See MaterialMaskData.
+    u32 material_mask;
+    /// EntityCollisionFilterInfo or ReceiverMask.
+    u32 collision_filter_info;
+    /// Contact layers we do not collide with.
+    /// One bit per ContactLayer -- layers are relative to the layer base value.
+    u32 ignored_layers;
+};
+
 class RigidBody : public sead::IDisposer, public RigidBase {
     SEAD_RTTI_BASE(RigidBody)
 public:
-    struct CollisionMasks {
-        /// See MaterialMaskData.
-        u32 material_mask;
-        /// EntityCollisionFilterInfo or ReceiverMask.
-        u32 collision_filter_info;
-        /// Contact layers we do not collide with.
-        /// One bit per ContactLayer -- layers are relative to the layer base value.
-        u32 ignored_layers;
-    };
+    using CollisionMasks = RigidBodyCollisionMasks;
 
     enum class Type {
         FromShape = 0,