Replacing [isolate || bidi-override] by isolate | bidi-override | isolate-override

Hi,

I'm working on WebKit's
implementation<https://bugs.webkit.org/show_bug.cgi?id=73164>of
unicode-bidi:
isolate bidi-override, and it came to our attention that it might be
simpler to just have isolate-override instead of allowing list of values
since only isolate/bidi-override combination is allowed.

Is there a plan/intention to expand the possible combinations or extend the
property in near future so that allowing a list of values is desirable? If
not, I would like to request to make the said change.

Best,
Ryosuke Niwa
Software Engineer
Google Inc.