URL should normalize host according to spec

[estrattonbailey]

The URL implementation used by this library doesn't appear to normalize URL hostnames in the same way as the implementations of Node 18 and WHATWG.

Here's a repro: https://replit.com/@estrattonbailey/URL-normalization

whatwg-url-without-unicode doesn't have Issues enabled or I would have filed there.

The spec says this:

Although host is case-insensitive, producers and normalizers should use lowercase for registered names and hexadecimal addresses for the sake of uniformity, while only using uppercase letters for percent-encodings.

[charpeni]

Thanks for flagging this and thanks for the repro, it was really convenient!

I'm not sure where this is coming from and why the test missed it, probably related to unicode.

It seems like we should be able to normalize this within whatwg-url-without-unicode by lowercasing them.

Will have a look at it.