[xhr] Status 0 is missing a message (#35)

It is hard to investigate status 0 errors, since they are [missing a statusText](https://fetch.spec.whatwg.org/#concept-network-error) value. A message would be very helpful, since it can have multiple reasons. (proxy, firewalls, broken cors, empty response...)



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Reply to this email directly or view it on GitHub:
https://github.com/whatwg/xhr/issues/35