bug#40193: 27.0.50; nxml-newline-and-indent argument should be optional

[Stefan Kangas]

close 40193 28.1
thanks

Sergey Trofimov <sarg@sarg.org.ru> writes:

> According to the definition of comment-line-break-function:
>   The function should take a single optional argument, which is a flag
>   indicating whether it should use soft newlines.
>
> But in nxml-mode:
>   (setq-local comment-line-break-function #'nxml-newline-and-indent)
>   (defun nxml-newline-and-indent (soft) ...)
>
> Could you please make an argument optional?

I've made this change on master; the fix will be in Emacs 28.1.