I propose something different. I think the current NR documentation is
right, with a usage description in the section of the NR, and a short
description from the docstring in the appendix that lists all music
functions. The reason I use the Identifiers page is that it's a quick read
of available functions -- if it gets longer because we have usage
instructions it won't be as useful to scan quickly.
If we want to move to having this documentation all in the music functions
(which may be a good idea, but will require some substantial rewriting of
the documentation building system, IMO), we should have *two* documentation
strings in the music function: 1) a description string, which is like the
current docstrings, and 2) a usage string, which is like the current text
from the NR.