The grammar groups this component together meaning that all
sub-components must occur together i.e.
`ordinal slashed-zero small-caps` is valid but
`ordinal small-caps slashed-zero` is not.
We also reuse the logic for parsing from the longhand
`font-variant-numeric` property for simplicity.
The grammar groups this component together meaning that all
sub-components must occur together i.e.
`common-ligatures no-contextual small-caps` is valid but
`common-ligatures small-caps no-contextual` is not.
We also reuse the logic for parsing from the longhand
`font-variant-ligatures` property for simplicity.
The grammar groups this component together meaning that all
sub-components must occur together i.e. `jis78 full-width small-caps` is
valid but `jis78 small-caps full-width` is not.
We also reuse the logic for parsing from the longhand
`font-variant-east-asian` property for simplicity.
