GDP: \articulation and -\articulation

[Graham Percival]

These are both valid:
{
  c'2-\accent
  c'2\accent
}

Should we keep the - version in the docs at all?  Does it really add
anything (especially since most people use the plain \ version) ?

It might be good as an introduction to ^ and _, but OTOH we
can do ^ and _ with items that don't have any -, such as
ties ~.

Cheers,
- Graham