Remove .html extension from links

chrome/common/extensions/docs/templates/articles/app_codelab7_useridentification.html

 <h1 id="lab_7_user_identity">Access User's Data</h1>
 
 <p>Most modern applications are attached to the web to synchronize data. When synchronizing data, you need to identify who the user is.
-Chrome Apps come with an <a href="experimental.identity.html">identity API</a> that makes it easy to integrate either with Google accounts or with any other service that supports OAuth.</p>
+Chrome Apps come with an <a href="experimental.identity">identity API</a> that makes it easy to integrate either with Google accounts or with any other service that supports OAuth.</p>
 
 <ol>
 <li> Built in - Google Authenticiation</li>
 <li> Third Party Authentication (Twitter, Foursquare, etc.)</li>
 </ol>
 
 <p class="warning"><b>Warning:</b>
 Apps with authentication require the experimental permission in the
 <code>manifest.json</code> and, until they came out of experimental state,
 they cannot be uploaded to the Chrome Web Store.
@@ skipping 157 matching lines @@
 
 <p>If you get stuck and want to see the app in action,
 go to <code>chrome://extensions</code>,
 load the unpacked
 <a href="https://github.com/GoogleChrome/chrome-app-codelab/tree/master/lab7_useridentification/angularjs">AngularJS app</a> or
 <a href="https://github.com/GoogleChrome/chrome-app-codelab/tree/master/lab7_useridentification/javascript">JavaScript app</a>,
 and launch the app from a new tab.</p>
 
 <h2 id="you_should_also_read">You should also read</h2>
 
-<p><a href="app_identity.html">Identify User</a> tutorial</p>
+<p><a href="app_identity">Identify User</a> tutorial</p>
 
 <h2 id="what_39_s_next_">What's next?</h2>
 
-<p>In <a href="app_codelab8_webresources.html">7 - Access Web Resources</a>,
+<p>In <a href="app_codelab8_webresources">7 - Access Web Resources</a>,
 you will learn how to load and show images from a remote URL.</p>
 
 <p class="note"><b>Note:</b>  Up until now, the code in each lab builds upon the previous lab code sample.
 We&#39;ve decided not to include the user identification code changes in the remainder of the lab since the <code>identity API</code> is still experimental and as such it would prevent you from publishing your final code to the Chrome Web Store.</p>