Broken error links.

[mikdiet]

https://git.io/??? links redirect to old repo name in github organisation.

This patch updates them with direct links on docs in the new repo.

~It's just an example of the issue (you don't have issues tab on your repo, otherwise I'd just submitted issue, not code change), I think there's more broken links + tests + you probably want to keep them shortened (and git.io doesn't accept new links).~

[rmosolgo]

Derp, I didn't realize there wasn't an issues tab. I just enabled it!

Anyways, I think this is definitely the right change. Would you mind updating the other references to git.io?

[mikdiet]

All right, I'll update the rest + tests by direct links.

[mikdiet]

@rmosolgo updated

[rmosolgo]

Thank you!