Dynamically generate a heading for Extension Docs API pages

chrome/common/extensions/api/history.json

 // 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.
 
 [
   {
     "namespace": "history",
+    "description": "Use the <code>chrome.history</code> module to intereact with the browser's record of visited pages. You can add, remove, and query for URLs in the browser's history. To override the history page with your own version, see <a href='override.html'>Override Pages</a>.",
     "types": [
       {
         "id": "HistoryItem",
         "type": "object",
         "description": "An object encapsulating one result of a history query.",
         "properties": {
           "id": {"type": "string", "minimum": 0, "description": "The unique identifier for the item."},
           "url": {"type": "string", "optional": true, "description": "The URL navigated to by a user."},
           "title": {"type": "string", "optional": true, "description": "The title of the page when it was last loaded."},
           "lastVisitTime": {"type": "number", "optional": true, "description": "When this page was last loaded, represented in milliseconds since the epoch."},
@@ skipping 153 matching lines @@
             "properties": {
               "allHistory": { "type": "boolean", "description": "True if all history was removed.  If true, then urls will be empty." },
               "urls": { "type": "array", "items": { "type": "string" }, "optional": true}
             }
           }
         ]
       }
     ]
   }
 ]