expose the concept of "primary" time zone identifier in Jiff #483
Description
Specifically, see: tc39/proposal-temporal#3249
And see: https://tc39.es/ecma402/#sup-availablenamedtimezoneidentifiers --- This defines how to determine whether a tzid is "primary" or not.
We could also expose lat/long coordinates and country codes too. We might as well since Jiff is already owning the reading of tzdb.
I don't think this results in any behavior changes. But would give users access to the rules Temporal (and ECMAScript and CLDR more broadly) use for marking tzids as "primary."