message: getrawtransaction: inform about blockhash argument when lookup fails
diff: @@ -196,7 +196,7 @@ static UniValue getrawtransaction(const JSONRPCRequest& request)
  }
  errmsg = "No such transaction found in the provided block";
  } else if (!g_txindex) {
  - errmsg = "No such mempool transaction. Use -txindex to enable blockchain transaction queries";
  + errmsg = "No such mempool transaction. Use -txindex or provide a block hash to enable blockchain transaction queries";
  } else if (!f_txindex_ready) {
  errmsg = "No such mempool transaction. Blockchain transactions are still in the process of being indexed";
  } else {
  