Exclude non-ASCII path or backslash in extended www autolink

[tats-u]

Related: #377

https://ドメイン名例.jp/を参照してください。

Should be "https://ドメイン名例.jp/を参照してください。" (<a href="https://xn--eckwd4c7cu47r2wf.jp/">https://ドメイン名例.jp/</a>を参照してください。).

> new URL("https://ドメイン名例.jp/例?q=例").toString()
'https://xn--eckwd4c7cu47r2wf.jp/%E4%BE%8B?q=%E4%BE%8B'

Note

"ドメイン例.jp" is equivalent to "example.jp" in Japanese language.

Warning

We should be careful of IDN homograph attack for user-generated Markdown.

If you copy an Unicode URL like above in the address bar of your browser, the path (after / after the domain) is escaped in Firefox and Chromium-based, and the Unicode domain become a puny code in Chromium-based.

This is offending mostly in Japanese and occasionally in Chinese and Korean.

Also, \ is converted to / if pasted to the address bar of your browser. It should be excluded, too.