doc: Add physics query workaround (#546)

This adds a workaround for using physics queries during the rollback
loop, without having to resort to full physics state rollbacks.

---------

Co-authored-by: Tamás Gálffy <ezittgtx@gmail.com>

Author: SchnozzleCat

docs/netfox/tutorials/rollback-caveats.md

@@ -72,6 +72,27 @@ i.e.
 * ChacacterBody (2D and 3D) - [move_and_collide()] ( which has a test only
   mode )
 
+While kinematic nodes like `CharacterBody3D` can be used with rollback, physics
+queries can still cause issues (e.g.
+`PhysicsDirectSpaceState3D.intersect_shape()`). This is due to the lack of
+updates mentioned earlier. To work around this, run the following for each
+`CollisionObject` that has its position rolled back before each tick of the
+rollback loop:
+
+```gdscript
+# Works for both Jolt and GodotPhysics3D.
+func _force_update_physics_transform():
+  PhysicsServer3D.body_set_mode(get_rid(), PhysicsServer3D.BODY_MODE_STATIC)
+  PhysicsServer3D.body_set_state(get_rid(), PhysicsServer3D.BODY_STATE_TRANSFORM, global_transform)
+  PhysicsServer3D.body_set_mode(get_rid(), PhysicsServer3D.BODY_MODE_KINEMATIC)
+```
+
+The above forces an update by setting the object to static, updating its
+transform, and then setting it back to its original, kinematic state.
+
+Note that the above code needs to run for any kinematic object that is to be
+detected by the query and is manipulated during rollback.
+
 !!!tip
     The *netfox.extras* addon provides optional support for physics simulation
     with rollback. See [Physics](../../netfox.extras/guides/physics.md)