default_port() takes a scheme but not a protocol()

[AlexandreBossard]

auto const myurl = url("https://exampe.com");
url::default_port(myurl.protocol()).has_value(); // false

So, protocol() returns https: but default_port() needs a scheme (no ':'). Plus, there is no url::scheme() provided. Is this some overlooking ? Having to strip the ':' every time is annoying.

[glynos]

That's a simple fix, I'd appreciate a short review of #136 to make sure I captured what you asked for.

[glynos]

Fixed in #136