trailing commas should be automatically added where necessary to avoid incorrect indentation

[DetachHead]

from #1100:

code

void foo({String? value, int? value2}) {}

String bar(String value) => "";

void main() {
  return foo(
    value: bar(
      "",
    )
  );
}

actual result

void foo({String? value, int? value2}) {}

String bar(String value) => "";

void main() {
  return foo(
      value: bar(
    "",
  ));
}

expected result

it could instead add the missing trailing comma so that it gets formatted correctly:

void main() {
  return foo(
    value: bar(
      "",
    ),
  );
}

irl example

this also screws up the tree lines in the flutter intellij plugin:

class _State extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return GestureDetector(
        child: Row(
      children: const [Text("Foo")],
    ));
  }
}

[srawlins]

Duplicate of #753?