[csswg-drafts] [css-shadow-parts-1] consider shorthand for forwarding multiple parts (#3421)

fergald has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-shadow-parts-1] consider shorthand for forwarding multiple parts ==
[spec](https://drafts.csswg.org/css-shadow-parts/#exportparts-attr)

E.g. "foo bar: buz" as shorthand for "foo: buz, bar: buz"
and/or
"foo: bar buz" as shorthand for "foo: bar, foo: buz"



Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/3421 using your GitHub account