bug#23061: 25.0.92; Docs of ARGLIST in byte-code function objects is outdated

[Eli Zaretskii]

> Date: Sat, 19 Mar 2016 15:58:05 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: Stefan Monnier <monnier@iro.umontreal.ca>
> 
>  (symbol-function 'backward-sexp)
>   => #[256 "\211\204^G^@\300\262^A\301^A[!\207" [1 forward-sexp] 3 1793299 
> "^p"]
> 
> IOW, instead of the argument list you have a number 256.  Neither the
> fact that it can be (and usually is) a number nor the ways to
> interpret that number are documented anywhere I could see.
> 
> It looks like the information about this can be found in
> byte-compile-make-args-desc and help-function-arglist.
> 
> The change which introduced this feature was done 5 years ago, so it's
> high time we had it documented.

Fixed.