Add support for -ms-lang's comma separated parameter

[rigdern]

-ms-lang's parameter can be a comma separated list (e.g. -ms-lang(am, ti)).

The parser fails to parse this rule:

.my-page:-ms-lang(am, ti) {
  font-family: "Ebrima";
}

But it can parse this rule where -ms-lang's parameter is just a single value.

.my-page:-ms-lang(am) {
  font-family: "Ebrima";
}

[kkirsche]

Closest I could find to documentation of -ms-lang https://msdn.microsoft.com/en-us/library/windows/apps/hh967757.aspx

[rigdern]

The remarks section of the MSDN documentation for lang talks a bit about -ms-lang:

In Internet Explorer 10, the :lang(C) pseudo-class accepts a comma-separated list of language codes. However, because this behavior is based on an early draft of the World Wide Web Consortium (W3C)'s Selectors Level 4 specification, you must add the "-ms-" vendor prefix to the pseudo-class to enable this functionality. In effect, the pseudo-class becomes :-ms-lang(C).