added doc comments about handling game object destruction

Author: StephenHodgson

Assets/MixedRealityToolkit/_Core/Interfaces/Devices/IMixedRealityControllerPoseSynchronizer.cs

@@ -20,6 +20,7 @@ public interface IMixedRealityControllerPoseSynchronizer : IMixedRealitySpatialI
         /// <summary>
         /// Should this <see cref="UnityEngine.GameObject"/> clean itself up when it's controller is lost?
         /// </summary>
+        /// <remarks>It's up to the implementation to properly destroy the <see cref="UnityEngine.GameObject"/>'s this interface will implement.</remarks>
         bool DestroyOnSourceLost { get; set; }
 
         /// <summary>