[fix] Ignore click event if href is mailto link

[baseballyama]

fix: #4045

I didn't know how to test this, so I didn't implement a test. Instead, I put a comment in the code.
If you have any ideas for the test, please let me know!

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[Conduitry]

Should we check for other custom URL schemes here as well? Is there a similar problem with, say, tel: links? Can we do this without hard coding specific schemes? It seems like any URL beginning with foo: should not be handled by the router and should be left to the browser.

[baseballyama]

@Conduitry

Ahh, this is really good point.

I think we can divert URL object.
Such mailto: or tel: doesn't have origin, so we can easily judge it by url.origin.

if (!is_svg_a_element && url.origin === 'null') return;

What do you think about it?

P.S: This might be helpful.
https://datatracker.ietf.org/doc/html/rfc3986#section-1.1.2

[Rich-Harris]

yeah, that looks like a good solution to me. thanks!