Turn a headline into a URL slug

Paste a title and watch the slug form as you type. Cyrillic is transliterated to Latin rather than stripped out or percent-encoded, so a Ukrainian headline gives a readable URL instead of an empty string or a wall of %D0%. Accents are folded, punctuation and emoji become separators, repeated separators collapse, and the ends are trimmed. Choose a hyphen or an underscore; Cyrillic is romanised under the Ukrainian standard.