bug#67527: 30.0.50; FR: Add an option to disable ispell completion in text-mode

[Eli Zaretskii]

> From: Eason Huang <aqua0210@foxmail.com>
> Cc: 67527@debbugs.gnu.org,  simon@ecksd.com
> Date: Sat, 13 Jan 2024 17:03:28 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > I guess I'm confused.  In your original report, which started this
> > discussion, you said:
> >
> >   Because when I enable the autocomplete by corfu or company, it will
> >   always popup the candidate when I input English characters.
> >   I don't want to diable the autocomplete of corfu or company, because I
> >   need it in org code block.
> >
> > I was asking about that part in your report -- how did the new support
> > for completion-at-point in text mode and its descendants change the
> > behavior when you enable autocomplete by corfu or company, and why
> > were you talking about disabling autocomplete of corfu and company?
> >
> 
> I have `cape-elisp-block` capf backend in org-buffer, and it only
> works in code block, that's why I need the autocomplete.
> 
> I also need the `flyspell-mode` in org-mode, the `flyspell-mode` will add
> ispell-completion-at-point to capf, but when I input characters in
> org-buffer, I don't need the ispell-completion-at-point backend.
> 
> Anyway, the below workaround works for me:
> 
> ```
> (add-hook 'text-mode-hook
>           (lambda ()
>             (remove-hook 'completion-at-point-functions 
> 'ispell-completion-at-point t)))
> ```

Thanks.

Eshel, given this feedback, I think it would make sense to add a new
defcustom that would make text-mode avoid adding
ispell-completion-at-point to completion-at-point-functions.  Would
you please submit such a change and the documentation changes to go
with it?  TIA.