bigint is not a completion keyword

[DanielRosenwasser]

function reallyReallyBigNumbers(m: bigint, n: bigint): b/**/ {
    if (m === 0n) {
        return n + 1n;
    }
    if (m > 0n && n === 0n) {
        return reallyReallyBigNumbers(m - 1n, 1n);
    }
    if (m > 0n && n > 0n) {
        return reallyReallyBigNumbers(m - 1n, n - 1n);
    }
    throw new Error("No negatives!");
}

Request completion at b and expect bigint in the list. It's actually not present.