In this flow, the bitcoin-wallet process acts as the client initiating the RPC request, while the bitcoin-node process acts as the server receiving it. So at “The getBlockHash method of the generated Chain server subclass in bitcoin-wallet receives a Cap’n Proto request object with the height parameter, and calls the getBlockHash method on its local Chain object with the provided height.” it should say bitcoin-node not bitcoin-wallet.
This PR fix this typo.