bug#19932: 25.0.50; doc string of `elisp--eval-last-sexp'

[Drew Adams]

> >> .. should not mention the prefix arg.  This is not a command, and the
> >> function code does not access `current-prefix-arg'.
> >
> > Maybe it should just be undocumented. It's a private function, and it
> > duplicates the docstring of its only caller.
> 
> FWIW, I like when functions are documented, even private ones.

Of course.  And "private" means nothing in the context of Emacs Lisp.

But perhaps some have dreams of turning it into C++. ;-)