Fix type inferencing and syntax coloring for DSLD constructor contributions

[eric-milles]

Consider the following:

class Bar {
}
class Foo {
  @groovy.transform.NamedVariant
  Foo(Bar bar) {
  }
  def makeThing() {
  }
  static factory() {
    new Foo().makeThing()
  }
}

When DSLD support is enabled, the method call "makeThing()" is highlighted as unknown (underlined) because the DSLD type lookup returns "void" for the type of "new Foo()".

[eric-milles]