bug#66636: Move lexical-binding warning from checkdoc to byte-compiler

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Eli Zaretskii <eliz@gnu.org>,  Mattias Engdegård
>  <mattias.engdegard@gmail.com>,  66636@debbugs.gnu.org,
>   stefankangas@gmail.com
> Date: Sun, 22 Oct 2023 00:12:51 -0400
> 
> >> FWIW, I think this would be a disservice to them (and to ourselves).
> >> In 99% of the cases it's just as easy to make the code work with
> >> `lexical-binding:t`.
> > I think we want to encourage whatever relieves users of the most work,
> > not what comports best with some abstract conception of desirability.
> 
> For users it should make no difference, they don't need to do anything
> (other than avert their eyes from the warning, maybe).

You interpret "users" in what I wrote too narrowly, I think.