Should `font-variant: none` be producing `font-feature-settings:"kern" off`?

[steveharrison]

I can't see any mention of kerning on https://developer.mozilla.org/en-US/docs/Web/CSS/font-variant: would it be more accurate to set font-feature-settings to normal instead? I've done a fix locally (just adding none: "normal" to the font-variant object in fontVariantProperties), but thought I'd check before raising a PR.