Remove trailing commas from Blink IDLs

Source/core/html/HTMLSelectElement.idl

 /*
  * Copyright (C) 2006, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 [
-    CustomIndexedSetter,
+    CustomIndexedSetter
 ] interface HTMLSelectElement : HTMLElement {
     [Reflect] attribute boolean autofocus;
     [Reflect] attribute boolean disabled;
     readonly attribute HTMLFormElement form;
     attribute boolean multiple;
     [Reflect] attribute DOMString name;
     [Reflect] attribute boolean required;
     attribute long size;
 
     readonly attribute DOMString type;
@@ skipping 13 matching lines @@
     [TreatNullAs=NullString] attribute DOMString value;
 
     readonly attribute boolean willValidate;
     readonly attribute ValidityState validity;
     readonly attribute DOMString validationMessage;
     boolean checkValidity();
     void setCustomValidity([TreatNullAs=NullString, TreatUndefinedAs=NullString] DOMString error);
 
     readonly attribute NodeList labels;
 };