Problem with `\acciaccatura` and `\cueDuring`

[Werner LEMBERG]

Consider this example.

```
fluteNotes = \relative {
  r2. c''4 |
  d8 \acciaccatura e c d e fis2 |
  g2 d |
}

oboeNotes = \relative c'' {
  R1 |
  \cueDuring "flute" #UP { R1 } |
  g2 d |
}

\addQuote "flute" { \fluteNotes }

<<
  \new Staff \fluteNotes
  \new Staff \oboeNotes
>>
```

As can be seen, the acciaccatura neither has a slash nor a slur if
quoted.  While it is (kind-of) acceptable that the slur gets
omitted[*], it's not ok that the slash is missing, especially if the
grace note's stem is overly long.

Is there a possibility to get the slash in an automated way (i.e., by
not being forced to replace `\cueDuring` with a manually added
`CueVoice`)?


    Werner


[*] AFAIK, I could change this globally by adding `slur-event` to
    `quotedCueEventTypes`, but this would bring in all legato slurs,
    too.