Fix type inferencing and syntax highlighting for qualified super expression

[eric-milles]

Consider the following:

interface I {
  static  bar() {}
  private baz() {}
  default foo() {
    I.bar()
    I.this.baz()
  }
}

class C implements I {
  @Override
  def foo() {
    I.super.foo()
  }
}

Method call expression "I.super.foo()" is showing as unknown (underlined). Groovy 5 supports native default methods, so this is no longer transformed into a trait helper call.

[eric-milles]