fix: expand text commentary for RPC encryptwallet

Author: knst

src/wallet/rpc/encrypt.cpp

@@ -252,7 +252,7 @@ RPCHelpMan encryptwallet()
         throw JSONRPCError(RPC_WALLET_ENCRYPTION_FAILED, "Error: Failed to encrypt the wallet.");
     }
 
-    return "wallet encrypted; The keypool has been flushed and a new HD seed was generated (if you are using HD). You need to make a new backup.";
+    return "wallet encrypted; The keypool has been flushed and a new HD seed was generated (if you are using HD). You need to make a new backup or write down the new seed (mnemonic).";
 },
     };
 }