uri format should allow protocol-relative urls

[legoktm]

Per https://tools.ietf.org/html/rfc3986#section-4.2 protocol-relative urls are valid (it claims they're "rarely used" but that's not true anymore).

Downstream MediaWiki bug is https://phabricator.wikimedia.org/T93010

[bighappyface]

Closed with #245

[legoktm]

Huh? What does #174 and phpunit have to do with this bug?

[bighappyface]

@legoktm good catch! I meant #245