QRestAccessManager: fix syncqt generation

Apparently it has trouble with multiple attributes between the
class keyword and the class name, looking only for the EXPORT
macros.

As a quick band-aid we can add the #pragma to tell syncqt
to generate the header explicitly.

Pick-to: 6.7
Fixes: QTBUG-123875
Change-Id: If155a5b667b9e71d43dfac04ad19caee0ff23793
Reviewed-by:  Alexey Edelev <alexey.edelev@qt.io>
Reviewed-by: Juha Vuolle <juha.vuolle@qt.io>

src/network/access/qrestaccessmanager.h

@@ -4,6 +4,10 @@
 #ifndef QRESTACCESSMANAGER_H
 #define QRESTACCESSMANAGER_H
 
+#if 0
+#pragma qt_class(QRestAccessManager)
+#endif
+
 #include <QtNetwork/qnetworkaccessmanager.h>
 
 QT_BEGIN_NAMESPACE