Note that QPalette::ColorRole must be kept in sync with QQuickColorGroup

Without adding the corresponding properties, they will not be available
in QML.

Task-number: QTBUG-116106
Pick-to: 6.6
Change-Id: I233e456ced585b9274a1724cc550bc2959757104
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

src/gui/kernel/qpalette.h

@@ -45,6 +45,7 @@ public:
     operator QVariant() const;
 
     // Do not change the order, the serialization format depends on it
+    // Ensure these values are kept in sync with QQuickColorGroup's properties.
     enum ColorGroup { Active, Disabled, Inactive, NColorGroups, Current, All, Normal = Active };
     Q_ENUM(ColorGroup)
     enum ColorRole { WindowText, Button, Light, Midlight, Dark, Mid,