Dynamically generate a heading for Extension Docs API pages

chrome/common/extensions/api/downloads.idl

 // 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.
 
+// Use the <code>chrome.downloads</code> API to programmatically initiate,
+// monitor, manipulate, and search for downloads.
+
 [permissions=downloads]
 namespace downloads {
   [inline_doc] dictionary HeaderNameValuePair {
     // Name of the HTTP header.
     DOMString name;
 
     // Value of the HTTP header.
     DOMString value;
   };
 
@@ skipping 457 matching lines @@
     // <code>FilenameSuggestion</code> object to <code>suggest</code> wins. In
     // order to avoid confusion regarding which extension will win, users should
     // not install extensions that may conflict. If the download is initiated by
     // $ref:download and the target filename is known before the MIME type and
     // tentative filename have been determined, use
     // <code>DownloadOptions.filename</code> instead.
     [maxListeners=1] static void onDeterminingFilename(
         DownloadItem downloadItem, SuggestFilenameCallback suggest);
   };
 };