bug#23135: [PATCH] Support completion of bang-rules in CSS mode

[Stefan Monnier]

> The attached patch adds support for completing bang-rules (rules that
> start with "!") in CSS and SCSS mode.

Looks fine, thanks.

> +        (list (point) pos (append (if sassy scss-bang-ids)
> +                                  css-bang-ids))))))

This duplicates code that's already elsewhere.  Maybe we should have
a new buffer-local var to keep the (s)css-bang-ids value appropriate for
the current mode.


        Stefan