GHI-#13 Use transparency for the scrollbar slider
GHI-#13 Use transparency for the scrollbar slider

This fixes right-side gutter code marker to be hidden underneath the
slider.
The slider background now uses a transparency of 66%. Active- and
hovered slider have a transparency of 60%.

arcticicestudio/nord-visual-studio-code,arcticicestudio/nord-visual-studio-code