Comment #3 on issue 2599 by [email protected]: Use of autochange http://code.google.com/p/lilypond/issues/detail?id=2599
Added as http://lsr.dsi.unimi.it/LSR/Item?id=849. This will automatically appear in the list of documented snippets, but not in the NR unless it's added. Not sure whether to add it or not.
