`gix_url::Url` `%`-encodes username in scp-like syntax

[yuja]

Current behavior 😯

This code generates the following output:

fn main() {
    let url = gix_url::parse("[email protected]:org/repo.git".as_ref()).unwrap();
    dbg!(&url);
    println!("{}", url.to_bstring());
}

[src/main.rs:3:5] &url = Url {
    scheme: Ssh,
    user: Some(
        "_git",
    ),
    password: None,
    host: Some(
        "source.example.tld",
    ),
    serialize_alternative_form: true,
    port: None,
    path: "org/repo.git",
}
%[email protected]:org/repo.git

Expected behavior 🤔

I'm not pretty sure, but Git appears not to decode %5Fgit back to _git.

This problem was originally reported as https://github.com/jj-vcs/jj/issues/6810.

Git behavior

No response

Steps to reproduce 🕹

No response