bug#64045: [PATCH] Improve wording of the documentation about declare form

[Shynur Xie]

>    From: Eli Zaretskii <eliz@gnu.org>
>    Date: Tue, 13 Jun 2023 16:46:47 +0300
> Subject: Re: bug#64045
>      To: Shynur Xie <one.last.kiss@outlook.com>
>
> So how about explaining what was wrong or missing or unclear in the
> original text?

You can read these 2 posts (very short and won't take up much of your
time):

- Question: Effect of `modes` In Declare Form
  https://emacs.stackexchange.com/questions/77597
- Question: `completion` In Declare Form Not Working
  https://emacs.stackexchange.com/questions/77599

Thanks.