elisp--get-fnsym-args-string
elisp--get-fnsym-args-string is a compiled Lisp function in `elisp-mode.el
'.
(elisp--get-fnsym-args-string SYM &optional INDEX)
Return a string containing the parameter list of the function SYM.
If SYM is a subr and no arglist is obtainable from the docstring
or elsewhere, return a 1-line docstring.