Dynamically generate a heading for Extension Docs API pages

chrome/common/extensions/api/tts_engine.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": "ttsEngine",
+    "description": "Use the <code>chrome.ttsEngine</code> module to implement a text-to-speech(TTS) engine using an extension. If your extension registers using this API, it will receive events containing an utterance to be spoken and other parameters when any extension or packaged app uses the <a href='tts.html'>tts</a> module to generate speech. Your extension can then use any available web technology to synthesize and output the speech, and send events back to the calling function to report the status.",
     "functions": [
       {
         "name": "sendTtsEvent",
         "nodoc": true,
         "type": "function",
         "description": "Routes a TTS event from a speech engine to a client.",
         "parameters": [
           {
             "type": "integer",
             "name": "requestId"
@@ skipping 76 matching lines @@
         ]
       },
       {
         "name": "onStop",
         "type": "function",
         "description": "Fired when a call is made to tts.stop and this extension may be in the middle of speaking. If an extension receives a call to onStop and speech is already stopped, it should do nothing (not raise an error)."
       }
     ]
   }
 ]