Editorial annotation improvements

• Incipits may be printed with various context types.

  \score {
    <<
      \new Staff \with { instrumentName = "MensuralStaff" }
        {
          \incipit { c'4 d' }
          c'4 d' e' f' g'1
        }
  
      \new Staff \with { instrumentName = "KievanStaff" }
        {
          \incipit \new KievanStaff { c'4 d' }
          c'4 d' e' f' g'1
        }
      \new Staff
        \with { instrumentName = "TabStaff" }
        {
          \incipit
            \new TabStaff
              \with { \magnifyStaff 0.5 \override InstrumentName.font-size = 6 }
              { c'4 d' }
          c'4 d' e' f' g'1
        }
    >>
    \layout {
      indent = 5\cm
      incipit-width = 2\cm
    }
  }
  

  

• Optional additional material can be enclosed in brackets that pass through the staff with \startOptionalMaterial and \stopOptionalMaterial.

  

• The FingerGlideSpanner may now connect StringNumber and StrokeFinger grobs.

  {
    \set strokeFingerOrientations = #'(down)
    b2 \glide -\rightHandFinger #1 \glide -2 \glide \5
    e'-\rightHandFinger #1 -2 \5
  }
  

  

• A new engraver, Toe_heel_engraver (enabled by default) listens to the context variable toeHeelStyle to provide styling options for the commands \rtoe, \ltoe, \rheel, and \lheel.

  music = { f'4\rtoe f'4\rheel f'4\ltoe f'4\lheel \bar "||" }
  
  {
    \music            % #'default
    \set toeHeelStyle = #'standard    \music
    \set toeHeelStyle = #'reversed    \music
    \set toeHeelStyle = #'below       \music
    \set toeHeelStyle = #'circleheels \music
  }
  

  

  If the engraver is enabled, these commands no longer behave like normal Script grobs since they ignore direction changes (i.e., ‘^’, ‘_’, and \tweak direction are ignored). If the need arises to position pedal marks individually, the new, standard articulation commands \toe, \vartoe, \heel, \varheel, and \heelcircle (accessing the new glyph scripts.pedalheelcircle) should be used instead.

  {
    f'2\toe f'2\vartoe |
    f'2\heel f'2\varheel |
    f'1\heelcircle
  }
  

  

  Removing the engraver makes \rtoe and siblings behave as in previous LilyPond versions.

• Directly related to the previous item are four new, articulation-like commands to indicate toe-heel and heel-toe substitutions, \ltoeheel, \rtoeheel, \lheeltoe, and \rheeltoe. They are influenced by the Toe_heel_engraver in the same way as \rtoe and siblings. Toe and heel glyphs have been harmonized in size to make these substitution marks look good.

  music = { f'4\rtoeheel f'4\rheeltoe
            f'4\ltoeheel f'4\lheeltoe \bar "||" }
  
  {
    \music            % #'default
    \set toeHeelStyle = #'standard    \music
    \set toeHeelStyle = #'reversed    \music
    \set toeHeelStyle = #'below       \music
    \set toeHeelStyle = #'circleheels \music
  }
  

  

• NoteName grobs are now horizontally centered by default.