Cleanup: fix some CSS comment styles (especially copyrights)

chrome/browser/resources/chromeos/first_run/preload.css

Index: chrome/browser/resources/chromeos/first_run/preload.css
diff --git a/chrome/browser/resources/chromeos/first_run/preload.css b/chrome/browser/resources/chromeos/first_run/preload.css
index 03baa02837dac278bfe411feb392e7e1e45fb3a8..36b9442745c2c6dbab5367c1189eb9ae85ef98f2 100644
--- a/chrome/browser/resources/chromeos/first_run/preload.css
+++ b/chrome/browser/resources/chromeos/first_run/preload.css
@@ -1,14 +1,10 @@
-/**
- * Copyright 2014 The Chromium Authors. All rights reserved.
+/* 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.
- */
+ * found in the LICENSE file. */
 
-/**
- * Preloads images. Without preloading, background image starts loading in
+/* Preloads images. Without preloading, background image starts loading in
  * the moment when CSS property is applied. Image loading has visible delay and
- * looks like defect.
- */
+ * looks like defect. */
 
 @media all and (-webkit-max-device-pixel-ratio: 1.5) {
   body::after {