Simplify the "responsive layout" implementation. Just use a QBoxLayout
with changing direction instead of repopulating a QGridLayout, and
change the orientation of one set of sliders instead of creating two
sets in a stacked layout.
Simplify the resizeEvent() implementation accordingly.
Update the documentation snippet text to match the code, and document
the resizeEvent() override.
Pick-to: 6.7 6.6
Fixes: QTBUG-119977
Change-Id: I73a1bb215c956fa283291ebf0ea45ff9a975c727
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>
f3fb89ba29