trailingCommas does not handle nested arrays

[ochristensen]

let a = [["a"]]

does not produce

let a = [["a",],]

as expected

[nicklockwood]

Trailing commas are only applied if the array is split over multiple lines, e.g.

let a = [
  [
    "a",
  ],
]

[ochristensen]

is there a rule to make that splitting happen automatically?

[nicklockwood]

@ochristensen only if the array literal exceeds the maxwidth value for lines, or if the array literal already contains a linebreak.