Mention a change to QDateTimeEdit::setDateTime()

I neglected to record the change in the Qt 6 changes documents that
help folk migrate from Qt 5. This is a follow-up to
commit 2a653fde48f7312ccd2f792d72d305061b410ae3

Fixes: QTBUG-97493
Pick-to: 6.2 6.2.1
Change-Id: Ie496fdd05759eeeac4c7610db40ab6745b5e0640
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

1 files changed, 13 insertions, 1 deletions

diff --git a/src/widgets/doc/src/qt6-changes.qdoc b/src/widgets/doc/src/qt6-changes.qdoc
index 1f8e97a4ad..c52b2645d1 100644
--- a/src/widgets/doc/src/qt6-changes.qdoc
+++ b/src/widgets/doc/src/qt6-changes.qdoc
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the documentation of the Qt Toolkit.
@@ -80,6 +80,18 @@
 
     The QComboBox::setModel() function is now virtual.
 
+    \section2 The QDateTimeEdit class
+
+    When QDateTimeEdit::setDateTime() is called with a date-time whose
+    time-spec doesn't match that of the QDateTimeEdit instance, the
+    date-time is converted to the time-spec of the QDateTimeEdit. This
+    gives a date-time that describes the same instant in time, but
+    does so in the same terms as the QDateTimeEdit uses. Previously,
+    the date and time from the passed date-time were combined with the
+    time-spec of the widget, ignoring the time-spec of the date-time;
+    this could describe a different point in time than the one
+    described by the date-time passed.
+
     \section1 ItemViews
 
     \section2 The QAbstractItemView class