The intention was always that you can define properties that do
not require a changed signal. But having to explicitly pass
a nullptr as signal parameter into the macro is ugly, so
use the cool QT_OVERLOADED_MACRO to make it optional.
Pick-to: 6.0
Change-Id: I0ce366d043850f983c968d73c544d89933c48df9
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
cb39ea0581