Replace most /TR/ links in IDL files

third_party/WebKit/Source/core/animation/AnimationTimeline.idl

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// http://www.w3.org/TR/web-animations/#the-animationtimeline-interface
+// https://w3c.github.io/web-animations/#the-animationtimeline-interface
 
 [
     RuntimeEnabled=WebAnimationsAPI,
 ] interface AnimationTimeline {
     attribute double? currentTime;
 
     // TODO(crbug.com/624639): Move getAnimations() to DocumentAnimatable
     sequence<Animation> getAnimations();
 };