Function parameters don't always wrap when using labeled and optional parameters

The following doesn't wrap with refmt even though the second line is > 80 characters.

let function_with_a_long_name =
    (~many=?, parameters, contained_in, this, definition, arguably, too_many) => {
  ();
  ();
};

This does wrap (similar line length, no labels):

let function_with_a_long_name =
    (
      many,
      parameters,
      contained_in,
      this,
      definition,
      arguably,
      too_many,
      wow,
    ) => {
  ();
  ();
};

This wraps too (more labels):

let function_with_a_long_name =
    (
      ~many=?,
      ~parameters,
      ~contained_in,
      this,
      definition,
      arguably,
      too_many,
    ) => {
  ();
  ();
};

Run refmt on the three Reason examples in the issue and compare the parameter-wrapping behavior. Locate the formatter logic for labeled and optional function parameters, then add coverage showing that the first example wraps as expected while preserving the existing cases.