Add native support for slash notation
In jazz leadsheet notation is often done to mark beat with slashes. Currently, MuseScore provides this facility via slash notehead and stemless notes, as in this snippet
This way to get the results as several drawbacks :
- When you transpose the score, the noteheads are transposed and there are not expected to move
- When you play the score, the notes are played even if slashed. A possible workaround is to adjust the velocity, but it can be cumbersome.
Add a way to change a rest into a slash (and back to a normal rest). Rests are note transposed and don't sound on playback.