message: rpc: improve TransactionDescriptionString() "generated" help
diff: @@ -1389,7 +1389,7 @@ static const std::vector<RPCResult> TransactionDescriptionString()
  {
  return{{RPCResult::Type::NUM, "confirmations", "The number of confirmations for the transaction. Negative confirmations means the\n"
  "transaction conflicted that many blocks ago."},
  - {RPCResult::Type::BOOL, "generated", /* optional */ true, "Only present if transaction only input is a coinbase one."},
  + {RPCResult::Type::BOOL, "generated", /* optional */ true, "Only present if the transaction's only input is a coinbase one."},
  {RPCResult::Type::BOOL, "trusted", /* optional */ true, "Whether we consider the transaction to be trusted and safe to spend from.\n"
  "Only present when the transaction has 0 confirmations (or negative confirmations, if conflicted)."},
  {RPCResult::Type::STR_HEX, "blockhash", /* optional */ true, "The block hash containing the transaction."},
  