-- /file.jsonc --
== should format with a trailing comma since we are inside of a JSONC file ==
{
  "testing": 123,
  "test1": [1, 2, 3],
  "test2": [
    1, 2, 3],
}

[expect]
{
  "testing": 123,
  "test1": [1, 2, 3],
  "test2": [
    1,
    2,
    3,
  ],
}