Clearer documentation/API for QModbusClient::processResponse()/processPrivateResponse()

Issues

• The concept of "private response" doesn't exist in Modbus literature.

• https://doc.qt.io/qt-6/qmodbusclient.html#processPrivateResponse doesn't explain what a "private response" is, or how it differs from QModbusClient::processResponse().

Suggestions

• Provide a clearer explanation in the documentation for QModbusClient::processPrivateResponse()
  • https://doc.qt.io/qt-6/qtserialbus-modbus-custom-example.html#custom-modbus-client seems to suggest that a "private response" is one from a custom function code - that explanation can be replicated under https://doc.qt.io/qt-6/qmodbusclient.html#processPrivateResponse

• Deprecate QModbusClient::processPrivateResponse()
  • Users sometimes need to reimplement QModbusClient::processResponse() anyway (see QTBUG-103879). Why not merge processResponse() and processPrivateResponse()?
  • If the plan is to retain both private and standard functions, it would be nice to have a clearer name instead (processCustomResponse? processNonStandardResponse?)