Feature request: allow port numbers for server-names or server-addresses

We received this request from a support customer:

Request

I have a zone set up like this:

zone "ednstest.example.com" {
     type static-stub;
     server-names {
          "srvr1-foo02.example.com";
          "srvr2-foo02.example.com";
     };
};

The owner of the zone asked me to test with his development server on port 8600, but there does not seem to be a way to specify a port number with this construction.

BIND already allows port number specifications in the "masters" and "forwarders" clauses, can it be allowed here too?

Links / references

From support ticket https://support.isc.org/Ticket/Display.html?id=13620