[csswg-drafts] [css-values] sin() and cos() can be negative (#4104)

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

== [css-values] sin() and cos() can be negative ==
https://drafts.csswg.org/css-values/#trig-funcs says

> `sin()` and `cos()` will always return a number between 0 and 1

But they can reach -1, e.g https://www.wolframalpha.com/input/?i=cos(pi)

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/4104 using your GitHub account