BSE: bsesong: fix missing notification for SongImpl::musical_tuning
BSE: bsesong: fix missing notification for SongImpl::musical_tuning

Signed-off-by: Tim Janik <6ec6ff229c4e1c5bbd5933ee92e6c5832ff023bb@gnu.org>

tim-janik/beast,swesterfeld/beast,tim-janik/beast,tim-janik/beast,tim-janik/beast,swesterfeld/beast,swesterfeld/beast,swesterfeld/beast,swesterfeld/beast,swesterfeld/beast,swesterfeld/beast,tim-janik/beast,tim-janik/beast,tim-janik/beast