bug#57397: cl-letf blindly macroexpands places

[Eli Zaretskii]

> From: Michael Heerdegen <michael_heerdegen@web.de>
> Cc: Stefan Monnier <monnier@iro.umontreal.ca>,  57397@debbugs.gnu.org,
>   larsi@gnus.org
> Date: Wed, 28 Sep 2022 19:10:59 +0200
> 
> We needed to say more clearly that the given lambda form must have an
> argument list of exactly one argument.

Then just say it, in these very words.