Deprecate the QStyleOptionProgressBar::orientation member

Its contents are already inside the "state" member.
Fixes a "TODO" for Qt 5 (bumping it to Qt 6, where we will be
able to break API).

[ChangeLog][QtWidgets][Styles] The usage of the
QStyleOptionProgressBar::orientation member has been deprecated.

Task-number: QTBUG-25121
Change-Id: Ie531bb2f2733b15a213e83c9706468e2bf829359
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

src/widgets/styles/qstyleoption.cpp

@@ -1634,6 +1634,9 @@ QStyleOptionProgressBar::QStyleOptionProgressBar(int version)
     \brief the progress bar's orientation (horizontal or vertical);
     the default orentation is Qt::Horizontal
 
+    \deprecated
+    Use the QStyle::State_Horizontal flag instead (in the the QStyleOption::state member).
+
     \sa QProgressBar::orientation
 */
 

src/widgets/styles/qstyleoption.h

@@ -325,7 +325,7 @@ public:
     QString text;
     Qt::Alignment textAlignment;
     bool textVisible;
-    Qt::Orientation orientation;
+    Qt::Orientation orientation; // ### Qt 6: remove
     bool invertedAppearance;
     bool bottomToTop;
 

src/widgets/widgets/qprogressbar.cpp

@@ -140,7 +140,7 @@ void QProgressBar::initStyleOption(QStyleOptionProgressBar *option) const
 
     if (QStyleOptionProgressBarV2 *optionV2
             = qstyleoption_cast<QStyleOptionProgressBarV2 *>(option)) {
-        optionV2->orientation = d->orientation;  // ### Qt 5: use State_Horizontal instead
+        optionV2->orientation = d->orientation;  // ### Qt 6: remove this member from QStyleOptionProgressBarV2
         optionV2->invertedAppearance = d->invertedAppearance;
         optionV2->bottomToTop = (d->textDirection == QProgressBar::BottomToTop);
     }