Re: Inferred function types in the *Help* buffer

[Eli Zaretskii <eliz@gnu.org>]

> From: Andrea Corallo <acorallo@gnu.org>
> Cc: Eli Zaretskii <eliz@gnu.org>,  emacs-devel@gnu.org
> Date: Tue, 30 May 2023 12:46:04 -0400
> 
> Okay I installed ecc1d990d9e into master to implement this, please let
> me know if the entry in NEWS can be improved or feel free to just do it
> (I'm terrible at writing).

The NEWS entry, viz.:

  ** Help
  ** 'describe-function' shows function inferred type when available.
  For native compiled Lisp functions 'describe-function' prints (after
  the signature) the automatically inferred function type as well.

Is IMO too terse.  "Inferred type" is terminology we didn't use and
don't explain the manual, so the above doesn't really tell what kind
of information is displayed.  We should give a hint, and perhaps have
more details in the ELisp manual, probably as part of documenting
subr-type.

> Also I'd like to improve this feature to list also the function types
> that are known to the compiler (Read `comp-known-type-specifiers').  ATM
> they lives in comp.el but would be better to move them out.

I don't necessarily see the reason.  We will probably move to having
native-compilation be the default, in which case comp.el will be
loaded in the majority of sessions quite soon after startup.  So it
doesn't make a lot of sense to try to move these out of comp.el.