As advocated in a ### Qt 6 comment.
[ChangeLog][QtCore][QItemSelectionRange] QItemSelectionRange no longer
supports ordering. The prior ordering was inconsistent with equality
and should not be needed.
Task-number: QTBUG-85700
Change-Id: I5eb372c203cae19db40fa67f706d911785652d5f
Reviewed-by: Lars Knoll <lars.knoll@qt.io>