Address review comments

src/field_effect_helpers.c

@@ -325,6 +325,7 @@ void UpdateTallGrassFieldEffect(struct Sprite * sprite)
         if ((objectEvent->currentCoords.x != sprite->data[1] || objectEvent->currentCoords.y != sprite->data[2]) && (objectEvent->previousCoords.x != sprite->data[1] || objectEvent->previousCoords.y != sprite->data[2]))
             sprite->data[7] = TRUE;
 
+        // This variable is misused.
         metatileBehavior = 0;
         if (sprite->animCmdIndex == 0)
             metatileBehavior = 4;