bug#8285: 24.0.50; doc of `imenu-generic-expression' and `imenu--generic-function'

["Drew Adams" <drew.adams@oracle.com>]

1. In the doc string of `imenu--generic-function', these terms are
completely undefined and unexplained: POSITION-MARKER, INDEX-NAME,
FUNCTION, ARGUMENTS, INDEX-POSITION, and INDEX-ALIST.  Please
define/explain these undefined terms.  If you don't understand the
problem, change these names to UU, VV, WW, XX, YY, and ZZ, and see if
you understand the doc.
 
2. Seems a bit odd that this internal-only function (judging by its
name, which contains `--') has all of the important doc for
`imenu-generic-expression'.  In the past, the latter's doc string
described the format.  Now the format is described (only) in the doc
string of an internal function.  This state, which seems inappropriate,
was introduced in Emacs 22.
 

In GNU Emacs 24.0.50.1 (i386-mingw-nt5.1.2600)
 of 2011-03-07 on 3249CTO
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.5) --no-opt --cflags
-Ic:/imagesupport/include'