Cleanup: fix some CSS comment styles (especially copyrights)

ui/webui/resources/css/tree.css

 /* Copyright (c) 2012 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. */
 
 tree {
   display: block;
   outline: none;
   overflow: auto;
 }
 
@@ skipping 45 matching lines @@
 .tree-row[has-children=false] .expand-icon {
   visibility: hidden;
 }
 
 .tree-row:hover {
   background-color: hsl(214, 91%, 97%);
   border-color: hsl(214, 91%, 85%);
   z-index: 1;
 }
 
-/*
-  WebKit has a bug with attribute selectors so we apply selected to the tree row
-  as well.
-
-  https://bugs.webkit.org/show_bug.cgi?id=12519
-
-*/
+/* WebKit has a bug with attribute selectors so we apply selected to the tree
+ * row as well. https://bugs.webkit.org/show_bug.cgi?id=12519. */
 .tree-row[selected] {
   background-image: -webkit-linear-gradient(rgba(255, 255, 255, 0.8),
                                             rgba(255,255,255,0));
 }
 
 .tree-row[selected] {
   background-color: hsl(0, 0%, 90%);
   border-color: hsl(0, 0%, 85%);
   z-index: 2;
 }
@@ skipping 87 matching lines @@
 <if expr="not is_macosx and not is_ios">
   outline: none;
 </if>
   padding: 1px 7px 1px 1px;
 }
 
 html[dir=rtl] .tree-item[editing] input {
   margin: -2px -3px -2px -8px;
   padding: 1px 1px 1px 7px;
 }