some docs use openMode flags from qt5. error: incomplete type ‘QIODevice’ used in nested name specifier

some parts of the docs still use old qt5 names

for example https://doc.qt.io/qt-6/qdatastream.html

QIODevice::ReadOnly should be QIODeviceBase::ReadOnly

QIODevice::WriteOnly should be QIODeviceBase::WriteOnly

... etc, according to https://doc.qt.io/qt-6/qiodevicebase.html#OpenModeFlag-enum

https://doc.qt.io/qt-6/qiodevice.html mentions only "WriteOnly flag" or "WriteOnly mode", but this should be explicit (QIODeviceBase::WriteOnly) and/or link to https://doc.qt.io/qt-6/qiodevicebase.html#OpenModeFlag-enum

using the old names with qt6 throws

error: incomplete type ‘QIODevice’ used in nested name specifier