bug#69387: 30.0.50; A string shouldn't be both a docstring and a return value

[Eli Zaretskii <eliz@gnu.org>]

> From: Mattias Engdegård <mattias.engdegard@gmail.com>
> Date: Tue, 5 Mar 2024 14:16:50 +0100
> Cc: monnier@iro.umontreal.ca,
>  69387@debbugs.gnu.org,
>  philipk@posteo.net
> 
> +** Returned strings are never docstrings
> +Functions and macros whose body consists of a single string literal now
> +only return that string; it is not used as a docstring.
> +Previously, that string was used as both a docstring and return value,
> +which was never what the programmer wanted.  This change applies to
> +'defun', 'defsubst', 'defmacro' and 'lambda' forms.
> +If you want the string to be a docstring, add an explicit return value.
> +
> +See related warning below.

Thanks, but please always remember to end the heading lines in NEWS
with a period.