Expressive mark improvements (LilyPond Changes)

### Expressive mark improvements

- The new commands `\chordSlur` and `\nonArpeggiato` support creating vertical slurs and brackets without abusing the `\arpeggio` command.

  >     { <c' g'>\nonArpeggiato <c' f''>\chordSlur }

- A new ornament, `bachschleifer`, is now available.

  >     { b' g''\bachschleifer }

- It is now possible to position `Script` to the left or right side of a `NoteHead`.

  >     { <c' g' c''\atRight \mordent e''>2 }

- Hairpins in the style of Ferneyhough now support al niente circles.

  >     {
  >       \override Hairpin.circled-tip = ##t
  >       \override Hairpin.stencil = #flared-hairpin
  >       b1\< b\> b\> b2 b\< b2 b\!
  >     }

- Two new variant glyphs for breathing signs are available: ‘laltcomma’ and ‘raltcomma’. These glyphs represent the old shapes of ‘lcomma’ and ‘rcomma’, respectively, before changing them to more common shapes.

  >     {
  >       \override BreathingSign.text =
  >         \markup { \musicglyph "scripts.raltcomma" }
  >       f'2 \breathe f' |
  >     }

- The wavy part of a `TrillSpanner` grob needs less vertical space now.

#### LilyPond Changes v2.26.0 (stable-branch).

- Major changes in LilyPond
  - Notes for source compilation and packagers
- New for musical notation
  - Pitches improvements
  - Rhythm improvements
  - Expressive mark improvements
  - Repeat improvements
  - Editorial annotation improvements
  - Text and font improvements
- New for specialist notation
- Miscellaneous improvements