Fix semantic highlighting of repeated annotations

Consider the following:
```groovy
@interface Bar {
  String one() default '1'
  String two() default '2'
}
@interface Bars {
  Bar[] value()
}

class C {
  @Bars([@Bar(one='x'), @Bar(one = 'y', two = 'z')])
  def m() {
  }
}
```

There is no syntax coloring of annotation attributes "one" and "two".