decrease minimumSkyBottomLineDistance to 1.0 again as slurs no longer collide

2.0 was too expansive, used too much space.
it was originally increased from 1.0 to 2.0 because there were slur collisions,
which are now avoided since slurs were added to the skyline and bottomline.

src/MusicalScore/Graphical/EngravingRules.ts

@@ -409,7 +409,7 @@ export class EngravingRules {
 
         // Line Widths
         this.minimumStaffLineDistance = 4.0;
-        this.minimumSkyBottomLineDistance = 2.0; // default. 1.0 for compacttight mode (1.0 can cause overlaps)
+        this.minimumSkyBottomLineDistance = 1.0; // default. compacttight mode sets it to 1.0 (as well).
         this.minimumCrossedBeamDifferenceMargin = 0.0001;
 
         // xSpacing Variables