DevTools: update buttons to new style

third_party/WebKit/Source/devtools/front_end/help/releaseNote.css

 /*
  * Copyright 2017 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.
  */
 
 :host {
 }
 
 .hbox {
@@ skipping 50 matching lines @@
     line-height: 13px;
     padding-bottom: 8px;
 }
 
 .release-note-container li:not(:hover) .release-note-subtitle {
     color: #999;
 }
 
 .release-note-action-container > button,
 .release-note-action-container > button:hover {
-    margin: 10px 20px;
-    background: none;
-    border: none;
+    margin: 10px 0 20px 20px;
     font-weight: 500;
     text-transform: uppercase;
     color: #757575;
-    font-size: 13px;
-}
-
-.release-note-action-container > button:hover {
     cursor: pointer;
-    color: #666;
 }
 
 .release-note-action-container {
     flex: none;
 }
 
 .release-note-image {
     flex-shrink: 2;
 }
 
 img {
     margin: 20px;
     width: 260px;
     height: 200px;
     flex: none;
     box-shadow: 0 2px 4px rgba(0, 0, 0, .3);
 }
 
 img:hover {
     box-shadow: 0 2px 4px rgba(0, 0, 0, .5);
 }