convert_to_for_in_iterable_indexed_loop

Convert a for-in loop to a for-in loop that uses iterable.indexed instead of iterable directly.

Before

void fn(Iterable<int> numbers) {
    for (final int number in numbers) {}
}

After

void fn(Iterable<int> numbers) {
    for (final (int index, int number) in numbers.indexed) {}
}