Apply Qt::ControlModifier to all spin box interactions

A step modifier already existed when scrolling with the
Qt::ControlModifier held. This patch applies this functionality to
other methods of stepping a spin box.

Holding the modifier increases the step rate when:
- scrolling;
- pressing the up/down keys;
- pressing the spin box up/down buttons.

[ChangeLog][QtWidgets][QAbstractSpinBox] The Qt::ControlModifier
increases the number of steps a QAbstractSpinBox takes for the
following interactions: scrolling, up/down keyboard keys and the spin
box buttons. Previously, Qt::ControlModifier only affected scrolling.

Task-number: QTBUG-67380
Change-Id: Icc8754d5c007da0771bfaef113603a2f334dd494
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/widgets/widgets/qabstractspinbox_p.h b/src/widgets/widgets/qabstractspinbox_p.h
index b8bc088160..fce88e43f4 100644
--- a/src/widgets/widgets/qabstractspinbox_p.h
+++ b/src/widgets/widgets/qabstractspinbox_p.h
@@ -146,6 +146,7 @@ public:
     uint ignoreUpdateEdit : 1;
     QAbstractSpinBox::CorrectionMode correctionMode;
     QAbstractSpinBox::StepType stepType = QAbstractSpinBox::StepType::DefaultStepType;
+    Qt::KeyboardModifier stepModifier = Qt::ControlModifier;
     int acceleration;
     QStyle::SubControl hoverControl;
     QRect hoverRect;