[css-cascade-5] Remove trailing `;` in `<import-condition>`

[cdoublev]

I think the trailing ; is a typo in the value definition of <import-condition>:

@import [ <url> | <string> ] [ layer | layer(<layer-name>) ]? <import-condition> ;
<import-condition> = [ supports( [ <supports-condition> | <declaration> ] ) ]? <media-query-list>? ;

[cdoublev]

Fixed in 95c2bfa.