An update: I haven't seen it properly resolve yet, but the support person i talked to said it's working on their end, so I guess it's down to DNS propagation at this point.
The DNS appears to be resolving correctly now, but Firefox and Chromium both hang on "Performing a TLS handshake to rustbyexample.com..." and finally time out. This happens regardless of typing http: or https:.
@steveklabnik, there's an HTTP server doing redirects on 80, but nothing listening for HTTPS or 443. (Or at least nothing responding.) The problem with that is that rustbyexample.com is in the HSTS preload list, so Chrome & Firefox will only try connecting on HTTPS.
Although, I'm not sure why it's working on your phone...
Okay so, I've decided that rather than use my host's apparently terribly broken redirect feature, I've pushed a tiny index that will do the redirect, and i've pointed the domain back at gh-pages. Sorry again, everyone, hopefully this takes care of it.
So i learned something new today; HSTS prevents me from manually creating HTTPS exceptions for websites.
I get the following error at the moment for rustbyexample.com Error code: SSL_ERROR_BAD_CERT_DOMAIN
Looks like the server provided a wildcard certificate for github.com.
Will this fix itself within the next hours?