Formatting of iterators is wrong

[lukaszcz]

The line breaks are inserted at the wrong places. For example,

main : Nat := fst <| for (longlongName1, longlongName2, longlongName3 := 4839248329, 10, 2438729) (x in [1;2;3;4;5;6;7]) {longlongName1 + longlongName2, longlongName1 * longlongName2, x + longlongName3};

is formatted to

main : Nat :=
  fst
    <| for (longlongName1, longlongName2, longlongName3 := 4839248329
      , 10
      , 2438729) (x in [1; 2; 3; 4; 5; 6; 7]) {
      longlongName1 + longlongName2
        , longlongName1 * longlongName2
        , x + longlongName3
    };

If the line needs to be broken, the formatter should break it after the for and then after the initializer. It should try to avoid breaking in the middle of the initializer or the range.