Add completion support for new pattern attribute of Newify AST transform

[eric-milles]

New in Groovy 2.5:

import groovy.transform.*

class Transforms {
  @Newify(pattern=/Hash.*/)
  void meth() {
    HashS|
  }
}

Code complete (Ctrl-Space) at | should include suggestions for HashSet constructors similar to case for @Newify(HashSet)