Clarify tram and train mappings

Specifically regarding the mapping from OSC 2.x.

Signed-off-by: Caspar de Haes <caspar.dehaes@five.ai>

Author: caspar-ai

osi_object.proto

@@ -841,29 +841,31 @@ message MovingObject
             //
             // This corresponds to "bicycle" in OpenScenario 1.x.
             //
-            // This is one of the OSI types which map from "VRU_vehicle" in OpenScenario 2.x.
+            // This is one of the OSI types which map from "bus" in OpenScenario 2.x.
             //
             TYPE_BICYCLE = 11;
 
             // Vehicle is a bus.
             //
             // This corresponds to "bus" in both OpenScenario 1.x and 2.x.
             //
+            // This is one of the OSI types which map from "bus" in OpenScenario 2.x.
+            //
             TYPE_BUS = 12;
 
             // Vehicle is a tram.
             //
             // This corresponds to "tram" in OpenScenario 1.x.
             //
-            // This has no equivalent in OpenScenario 2.x.
+            // This is one of the OSI types which map from "bus" in OpenScenario 2.x.
             //
             TYPE_TRAM = 13;
 
             // Vehicle is a train.
             //
             // This corresponds to "train" in OpenScenario 1.x.
             //
-            // This has no equivalent in OpenScenario 2.x.
+            // This is one of the OSI types which map from "bus" in OpenScenario 2.x.
             //
             TYPE_TRAIN = 14;