Fix #5997: Add missing parentheses

[nicolasstucki]

No description provided.

[abgruszecki]

Hijacking, since I approve of anything that adds parentheses.

Looks mostly good to me, but I think that printQual should also be used when printing match and function application:

$ cat test.scala
class C {
  def foo(x: Boolean) = !x
  def bar() = (if true then 1 else 2) match { case x => x }
  def baz() = (if true then identity else identity)(0)
}
$ ../bin/dotc -decompile C
/** Decompiled from ./C.tasty */
class C() {
  def foo(x: scala.Boolean): scala.Boolean = x.unary_!
  def bar(): scala.Int = if (true) 1 else 2 match {
    case x =>
      (x: scala.Int)
  }
  def baz(): scala.Any = if (true) ((x: scala.Any) => scala.Predef.identity[scala.Any](x)) else ((x: scala.Any) => scala.Predef.identity[scala.Any](x)).apply(0)

Fixed other cases