QFile/QFileInfo::readLink() functions are obsolete but were not marked
as deprecated.
Explicit mark them as deprecated so they can be removed with Qt6.
Change-Id: I52424dc5441e1f5b01015713df990bbec5186caa
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@qt.io>