npostavs@users.sourceforge.net writes:

>     (defun foo (&rest args)
>       "Do foo.
>
>     \(fn ARG1 ARG2)")
>
>     (help-function-arglist 'foo) ;=> (&rest args)

Here's a patch which puts the check of the docstring before the lambda
list.  I'm not sure what to do with the PRESERVE-NAMES argument of
`help-function-arglist' though.