Document some recent service protocol features

runtime/vm/json_stream.h

Index: runtime/vm/json_stream.h
diff --git a/runtime/vm/json_stream.h b/runtime/vm/json_stream.h
index e49b8468609aeff996b4413223b812e71a78b50d..6f4e85a19bf4a7214eb5b782cc2823cdea333874 100644
--- a/runtime/vm/json_stream.h
+++ b/runtime/vm/json_stream.h
@@ -56,14 +56,13 @@ enum JSONRpcErrorCode {
   kIsolateMustBeRunnable = 105,
   kIsolateMustBePaused = 106,
   kCannotResume = 107,
+  kIsolateIsReloading = 108,
+  kIsolateReloadBarred = 109,
 
   // Experimental (used in private rpcs).
-  kIsolateIsReloading = 1000,
   kFileSystemAlreadyExists = 1001,
   kFileSystemDoesNotExist = 1002,
   kFileDoesNotExist = 1003,
-  kIsolateReloadFailed = 1004,
-  kIsolateReloadBarred = 1005,
 };
 
 // Expected that user_data is a JSONStream*.