Fix volume and duration slider mouse wheel events
Moved the MouseArea to inside the slider. Previously the Slider was overriding the MouseArea and wheel events were not working correctly.
Also added a tooltip to the volume slider.
The duration slider is very choppy but it was like that before.
Before: simplescreenrecorder-2022-04-04_12.19.46.mkv
After: simplescreenrecorder-2022-04-04_14.27.38.mkv
Edit: This sort of fixes 450984 since this ignores the default slider scroll event.
Edited by Jack Hill