[css-fonts-4] MapClass is removed from IDL spec

[saschanaz]

CSSFontFeatureValuesMap uses MapClass extended attribute:

[MapClass(CSSOMString, sequence<unsigned long>)]
interface CSSFontFeatureValuesMap {
  void set(CSSOMString featureValueName,
           (unsigned long or sequence<unsigned long>) values);
}

But it's removed and replaced by maplike: whatwg/webidl@1bc1e29 (Although the commit message improperly refers MapClass as MapLike)

[svgeesus]

MapLike

[svgeesus]

Fixed by 713ace7