bug#60860: 29.0.60; set save-silently to t can not avoid messages when saving files

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: Eli Zaretskii <eliz@gnu.org>,  60860@debbugs.gnu.org
> Date: Fri, 31 Mar 2023 19:03:16 +0300
> 
> >> To do the same, in Emacs 29 it's possible to add all these strings
> >> like "Saving file..." to 'inhibit-message-regexps'.
> >
> > I tried to set (setq inhibit-message-regexps "^Saving"), but the message
> > in acho area still exist when saving file.
> 
> Please also customize 'set-message-functions' so that its first element
> is 'inhibit-message'.  Also 'inhibit-message-regexps' should be a list.
> These settings should disable the message:
> 
>   (setq inhibit-message-regexps '("^Saving"))
>   (setq set-message-functions '(inhibit-message))

Why wasn't any of this documented?..