Update osi_object.proto

Deleted x-axis in the description.

Co-authored-by: caspar-ai <caspar.dehaes@five.ai>

Author: ThomasNaderBMW

osi_object.proto

@@ -495,8 +495,7 @@ message MovingObject
             // Orientation of the wheel.
             //
             // The reference system is the vehicle frame (center of bounding box).
-            // Right-handed, x-axis shows into driving direction "forward".
-            // Rough Approximation: The yaw-value shows the steering angle.
+            // Right-handed relative to the vehicle's forward motion.  The yaw-value shows the steering angle.
             //
             optional Orientation3d orientation = 7;