Since we cannot re-use the pre-existing QPartialOrdering type due to
binary-compatibility issues (it's not BC to std::partial_ordering),
we're no longer bound to copy its API for consistency.
So copy std::*_ordering type API for consistency instead, to ease
porting for users that can already use C++20 and everyone else come
Qt 7.
This patch is another step in that direction, renaming classes and
their memmbers to std-compatible names. QPartialOrdering cannot
change, as it's pre-existing. So add a completely new type
Qt::partial_ordering.
Adding conversions from QPartialOrdering is left for a follow-up
patch.
As a drive-by, change `\c Less` to `\l Less` in the \class
documentation blocks of the new classes.
Amending c6fe64b17c, which didn't have a
ChangeLog:
[ChangeLog][QtCore] Added Qt::{partial,weak,strong}_ordering as
drop-in C++17 stand-ins for C++20's std::{partial,weak,strong}_ordering.
Task-number: QTBUG-119108
Change-Id: Ib1296de6b708571a6abca8843ba36c114f6fd34f
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
bdd41f491c