Function isAltGrChar

docs/components/editor.js:89–89

(e)

    // AltGr emits a printable char while flagging Ctrl+Alt; real Ctrl+Alt shortcuts produce a letter/digit `key`.
    const isAltGrChar = (e) => e.ctrlKey && e.altKey && e.key.length === 1 && !/^[A-Za-z0-9]$/.test(e.key);

    // mutable state