bug#40750: Use error face for errors

[Stefan Kangas]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> ndame <ndame@protonmail.com> writes:
>
>> There is a standard face: error, which is red by default.
>>
>> Error messages in emacs should use it. It makes errors more conspicuous in
>> the echo area and the Messages buffer, distinguishing them from regular
>> messages.
>
> I think having Emacs using red for error message in the echo area etc
> would look pretty odd?  Anybody got an opinion here?

It's hard to say without seeing it in practice.

I think having a face here would be interesting, even if it just looks
like the default face.  That would open the door for experimentation in
third-party themes, and perhaps they will come up with some good ideas
that we will want to imitate.

(See also Bug#50785.)