Merge PR Agoric#40: Update app-complete.md

Author: EG-easy

tutorial/app-complete.md

@@ -261,7 +261,7 @@ func MakeCodec() *codec.Codec {
 	auth.RegisterCodec(cdc)
 	bank.RegisterCodec(cdc)
 	nameservice.RegisterCodec(cdc)
-	stake.RegisterCodec(cdc)
+	staking.RegisterCodec(cdc)
 	sdk.RegisterCodec(cdc)
 	codec.RegisterCrypto(cdc)
 	return cdc