docs: @Override
      public void visitExtendsClause(GroovySourceAST t, int visit) {
          SimpleGroovyClassDoc currentClassDoc = getCurrentClassDoc();
          if (visit == OPENING_VISIT) {
              for (GroovySourceAST superClassNode : findTypeNames(t)) {
                  String superClassName = extractName(superClassNode);
                  if (currentClassDoc.isInterface()) {
                      currentClassDoc.addInterfaceName(superClassName);
                  } else {
                      currentClassDoc.setSuperClassName(superClassName);
                  }
              }
          }
      }