Product with multi-line prefix will break display.

[tribbloid]

Here is a simple example.

  val nodeStr = s"""
                   |[A]
                   |[B]
                   |""".stripMargin.trim

  case class Prod(prefix: String)(vs: Any*) extends Product {
    override def productPrefix: String = prefix

    override def productArity: Int = vs.size

    override def productElement(n: Int): Any = vs(n)
  }

  it("try it another time") {

    val v = Prod(nodeStr)(
      Prod(nodeStr)(
        Prod(nodeStr)(),
        Prod(nodeStr)()
      )
    )

    pprint.pprintln(v)
  }

Output:

[A]
[B](
  [A]
[B](
    [A]
[B](),
    [A]
[B]()
  )
)

Most indentations of [B] are wrong.

Also, I wonder if I can submit a quick patch to customise parenthesis, indentation characters, and comma space? Combining with a fix of the above issue, it will be capable of pprint arbitrary trees (e.g. a Spark SQL LogicalPlan)