Adapt to Qt6 text codec changes
In Qt6 QTextCodec/QTextStream::setCodec is replaced with QTextStream::setEncoding(QStringConverter::Encoding)
Also UTF-8 is the new default for QTextStream.
In Qt6 QTextCodec/QTextStream::setCodec is replaced with QTextStream::setEncoding(QStringConverter::Encoding)
Also UTF-8 is the new default for QTextStream.