Use as much as possible of the 64b hash in Qt6

src/common/hash.h

@@ -6,13 +6,13 @@
 
 #if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
 #define HASH_T uint
+
+inline uint qHash(const QPoint &p)
+{
+	return qHash(QPair<int, int>(p.x(), p.y()));
+}
 #else // QT6
 #define HASH_T size_t
 #endif // QT6
 
-inline HASH_T qHash(const QPoint &p)
-{
-	return ::qHash(p.x()) ^ ::qHash(p.y());
-}
-
 #endif // HASH_H