Extensions Docs Server: Fix headings with no IDs

chrome/common/extensions/docs/templates/articles/overview.html

 <h1>Overview</h1>
 
 
 <p>
 Once you've finished this page
 and the
 <a href="getstarted.html">Getting Started</a> tutorial,
 you'll be all set to start writing extensions and packaged apps.
 </p>
 
@@ skipping 193 matching lines @@
 When you package an extension
 (typically, by uploading it with the dashboard),
 the extension gets a permanent ID,
 which remains the same even after you update the extension.
 Once the extension ID is permanent,
 you can change all occurrences of
 <code>@@extension_id</code> to use the real ID.
 </p>
 
 
-<h3>The manifest file</h3>
+<h3 id="manifest">The manifest file</h3>
 
 <p>
 The manifest file, called <code>manifest.json</code>,
 gives information about the extension,
 such as the most important files
 and the capabilities that the extension might use.
 Here's a typical manifest file for a browser action
 that uses information from google.com:
 </p>
 
@@ skipping 408 matching lines @@
 <ul>
   <li> <a href="getstarted.html">Tutorial: Getting Started</a> </li>
   <li> <a href="tut_debugging.html">Tutorial: Debugging</a> </li>
   <li> <a href="devguide.html">Developer's Guide</a> </li>
   <li> <a href="http://dev.chromium.org/developers/design-documents/extensions/samples">Samples</a> </li>
   <li> <a href="http://www.youtube.com/view_play_list?p=CA101D6A85FE9D4B">Videos</a>,
     such as
     <a href="http://www.youtube.com/watch?v=B4M_a7xejYI&feature=PlayList&p=CA101D6A85FE9D4B&index=6">Extension Message Passing</a>
     </li>
 </ul>