Update names in subscribe portion of sync protocol

rojo-test/serve-test-snapshots/serve_test__add_folder_subscribe.snap

@@ -4,7 +4,7 @@ expression: "subscribe_response.intern_and_redact(&mut redactions, ())"
 ---
 messageCursor: 1
 messages:
-  - addedInstances:
+  - added:
       id-3:
         Children: []
         ClassName: Folder
@@ -14,6 +14,6 @@ messages:
         Name: my-new-folder
         Parent: id-2
         Properties: {}
-    removedInstances: []
-    updatedInstances: []
+    removed: []
+    updated: []
 sessionId: id-1