Nested named tuple types aren't downleveled

[mmkal]

Repro (bash):

echo 'export type A = [one: 1, two: [three: 3, four: 4]]' > test.d.ts
npx [email protected] test.d.ts out.d.ts
cat out.d.ts

Result:

export type A = [
    /*one*/ 1,
    /*two*/ [
        three: 3,
        four: 4
    ]
];

Expected:

export type A = [
    /*one*/ 1,
    /*two*/ [
        /*three*/ 3,
        /*four*/ 4
    ]
];

This can be worked around by running downlevel-dts multiple times, but it's hard to know how many!