docs(connection-approval.md): added some extra info about prefab hashes

Author: jdcook

docs/_docs/getting-started/connection-approval.md

@@ -19,7 +19,9 @@ private void ApprovalCheck(byte[] connectionData, ulong clientId, MLAPI.Networki
     bool approve = true;
     bool createPlayerObject = true;
 
-    ulong? prefabHash = SpawnManager.GetPrefabHashFromGenerator("MyPrefabHashGenerator"); // The prefab hash. Use null to use the default player prefab
+    // The prefab hash. Use null to use the default player prefab
+    // If using this hash, replace "MyPrefabHashGenerator" with the name of a prefab added to the NetworkedPrefabs field of your NetworkingManager object in the scene
+    ulong? prefabHash = SpawnManager.GetPrefabHashFromGenerator("MyPrefabHashGenerator");
 
     //If approve is true, the connection gets added. If it's false. The client gets disconnected
     callback(createPlayerObject, prefabHash, approve, positionToSpawnAt, rotationToSpawnWith);