Forward headers are not generated for deprecated classes

The syncqt.pl script is not able to find the class names marked with QT_DEPRECATED.* macros. Therefore, no headers in the "include/" directory are generated for such classes. For example:

class QT_DEPRECATED_VERSION_X(5, 15, "message") Q_XML_EXPORT QXmlReader
{
...
}

No "include/QtXml/QXmlReader" header will be generated. That makes impossible deprecating entire classes.

As a workaround we can deprecate only the constructors, but it would be better if we could deprecate the class itself.