Dynamically generate a heading for Extension Docs API pages

chrome/common/extensions/api/web_navigation.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": "webNavigation",
+    "description": "Use the <code>chrome.webNavigation</code> module to receive notifications about the status of navigations requests in-flight.",
     "types": [],
     "functions": [
       {
         "name": "getFrame",
         "type": "function",
         "description": "Retrieves information about the given frame. A frame refers to an &lt;iframe&gt; or a &lt;frame&gt; of a web page and is identified by a tab ID and a frame ID.",
         "parameters": [
           {
             "type": "object",
             "name": "details",
@@ skipping 311 matching lines @@
               "transitionType": {"type": "string", "enum": ["link", "typed", "auto_bookmark", "auto_subframe", "manual_subframe", "generated", "start_page", "form_submit", "reload", "keyword", "keyword_generated"], "description": "Cause of the navigation. The same transition types as defined in the history API are used."},
               "transitionQualifiers": {"type": "array", "description": "A list of transition qualifiers.", "items": {"type": "string", "enum": ["client_redirect", "server_redirect", "forward_back", "from_address_bar"]}},
               "timeStamp": {"type": "number", "description": "The time when the navigation was committed, in milliseconds since the epoch."}
             }
           }
         ]
       }
     ]
   }
 ]