code: public AnnotationTypeDoc annotationType() {
          ClassSymbol atsym = (ClassSymbol)annotation.type.tsym;
          if (annotation.type.isErroneous()) {
              env.warning(null, "javadoc.class_not_found", annotation.type.toString());
              return new AnnotationTypeDocImpl(env, atsym);
          } else {
              return (AnnotationTypeDoc)env.getClassDoc(atsym);
          }
      }
docs: Returns the annotation type of this annotation.