Re: Chord names collide with span bar

[Werner LEMBERG]

>>> I remembered that you can add the Bar_engraver to ChordNames.
>>> Making them transparent so they do not visually interfere with the
>>> SpanBar, but they still take up space.
>>
>> Nice!  This begs the question whether we have a real bug or 'just'
>> insufficient documentation...
>
> I was thinking about commands like \textLengthOn.  Would there be
> value in providing a more consistent way to handle this use case
> without having to manually do what I did?  It feels a little bit
> hacky to be instantiating transparent BarLines.  I could see an LSR
> snippet being created to demonstrate the technique, but would we
> want it in the docs?

I think I've found the real fix for the problem.  Suddenly remembering
that we already have the `Span_bar_stub_engraver` to handle exactly
such situations I wondered why it works for lyrics but not for chord
names.  Comparing the definitions of the two contexts in
`engraver-init.ly` I found out that the `Pure_from_neighbor_engraver`
was missing, and adding it seems to do the trick.


```
\version "2.25.13"

\layout {
  \context {
    \ChordNames
    \consists Pure_from_neighbor_engraver
  }
}

\score {
  \new GrandStaff <<
    \new Staff \relative { c''4 c c c | c c c c }
    \new ChordNames \chordmode { c2. q8. des16:maj9 | q1 }
    \new Staff { \improvisationOn b'4 4 4 8. 16~ | 4 4 4 4 }
  >>
}
```


Since I don't have experience with chord names I ask users who need
this feature to check whether it works as expected in general.


    Werner