sharing specs move to line of previous spec

[HarrisonGrodin]

sharing specs seem to jump on the same line as existing code. For example, this:

signature S =
  sig
    type t1
    type t2

    sharing type t1 = t2
  end

autoformats to:

signature S =
  sig
    type t1
    type t2 sharing type t1 = t2
  end