feat(Options): add osmd.EngravingRules.LyricsYOffsetToStaffHeight (#865)

the EngravingRule was there before, but unused.
(so the effective default was 0)

fix #865

src/MusicalScore/Graphical/EngravingRules.ts

@@ -413,7 +413,7 @@ export class EngravingRules {
         // Lyrics
         this.LyricsAlignmentStandard = TextAlignmentEnum.LeftBottom; // CenterBottom and LeftBottom tested, spacing-optimized
         this.LyricsHeight = 2.0; // actually size of lyrics
-        this.LyricsYOffsetToStaffHeight = 3.0; // distance between lyrics and staff. could partly be even lower/dynamic
+        this.LyricsYOffsetToStaffHeight = 0.0; // distance between lyrics and staff. could partly be even lower/dynamic
         this.VerticalBetweenLyricsDistance = 0.5;
         this.HorizontalBetweenLyricsDistance = 0.2;
         this.BetweenSyllableMaximumDistance = 10.0;

src/MusicalScore/Graphical/MusicSheetCalculator.ts

@@ -571,7 +571,8 @@ export abstract class MusicSheetCalculator {
                 // eg verseNumbers: 2,3,4,6 => 1,2,3,4
                 const verseNumber: number = lyricEntry.LyricsEntry.VerseNumber;
                 const sortedLyricVerseNumberIndex: number = lyricVersesNumber.indexOf(verseNumber);
-                const firstPosition: number = lyricsStartYPosition + this.rules.LyricsHeight + this.rules.VerticalBetweenLyricsDistance;
+                const firstPosition: number = lyricsStartYPosition + this.rules.LyricsHeight + this.rules.VerticalBetweenLyricsDistance +
+                    this.rules.LyricsYOffsetToStaffHeight;
 
                 // Y-position calculated according to aforementioned mapping
                 let position: number = firstPosition + (this.rules.VerticalBetweenLyricsDistance + this.rules.LyricsHeight) * sortedLyricVerseNumberIndex;