Remove .html extension from links

chrome/common/extensions/docs/templates/articles/app_codelab6_lifecycle.html

 <h1 id="lab_6_lifecycle">Manage App Lifecycle</h1>
 
 <p>Like everything in this world, apps have a lifecycle.  They are installed, launched, restarted, suspended when the system needs to free up resources and uninstalled.  This lab will show you the basics of the Chrome app lifecycle and how its heart, the event page (aka background script), is used.</p>
 
 <h2 id="the_event_page">The event page</h2>
 
 <p>The event page is one of the most important pieces of a Chrome app. It&#39;s responsible for what gets launched, when, and how.
 For example, if your app is an instant messenger, you might want your event page to only show a UI when there is a new notification.</p>
 
 <p>For simpler apps, the event page listens to the app lifecycle events and reacts appropriately.
@@ skipping 17 matching lines @@
 <p>Execute your app as it is now, move and resize the window,
 close and restart it.
 The app will reopen in the original location, right?
 Now add a property <code>id</code> to the event page,
 <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab6_lifecycle/angularjs/main.js">Angular main.js</a> or
 <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab6_lifecycle/javascript/main.js">JavaScript main.js</a>,
 reload the app and test again:</p>
 
 <pre data-filename="main.js">
 chrome.app.runtime.onLaunched.addListener(function() {
-    chrome.app.window.create(&#39;index.html&#39;,
+    chrome.app.window.create(&#39;index&#39;,
       {id: &#39;mainwindow&#39;, bounds: {width: 500, height: 309} });
   });
 </pre>
 
 <p>If your application requires, you can open more than one window.</p>
 
 <h2 id="the_onrestarted_event">The onRestarted event</h2>
 
 <p>The $(ref:app.runtime.onRestarted) event is not as essential as <code>onLaunched</code>,
 but it might be relevant to certain types of apps.
 This event is executed when the app is restarted, for example,
 when Chrome quits, restarts, and the app is launched again.
 You can use this event to restore a transient state.</p>
 
 <p>For example, if your app has a form with several fields,
 you won&#39;t always want to save the partial form while the user is typing.
 If the user quits the app on purpose, she might not be interested keeping the partial data.
 If the Chrome runtime restarted for some reason other than by a user&#39;s intention,
 the user will want that data when the app is restarted.</p>
 
 <p>Let&#39;s change our code to save the Todo input field in $(ref:storage) as the user types,
 only restoring it if the <code>onRestarted</code> event is triggered.</p>
 
 <p class="note"><b>Note:</b>
 We learned about <code>chrome.storage.sync</code> before, but
-<a href="storage.html#using-sync">chrome.storage.local</a>
+<a href="storage#using-sync">chrome.storage.local</a>
 wasn&#39;t mentioned until now.
 Both have exactly the same syntax,
 but the semantics of <code>chrome.storage.local</code> is, as the name says, completely local.
 There&#39;s no attempt to synchronize or to save the data in the cloud.</p>
 
 <h3 id="event-page">Update event page</h3>
 
 <p>Update the event page to include the
 <code>onLaunched</code> and <code>onRestarted</code> events.
 Events are handled the same in
 <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab6_lifecycle/angularjs/main.js">AngularJS main.js</a> and
 <a href="https://github.com/GoogleChrome/chrome-app-codelab/blob/master/lab6_lifecycle/javascript/main.js">JavaScript main.js</a>:
 </p>
 
 <pre data-filename="main.js">
 chrome.app.runtime.onLaunched.addListener(function() {
   // normal launch initiated by the user, let&#39;s start clean.
   // note that this is not related to the persistent state, which is
   // appropriately handled in the window code.
   runApp(false);
 });
 
 chrome.app.runtime.onRestarted.addListener(function() {
   // if restarted, try to get the transient saved state
   runApp(true);
 });
 
 function runApp(readInitialState) {
-  chrome.app.window.create(&#39;index.html&#39;,
+  chrome.app.window.create(&#39;index&#39;,
     {id: &#39;mainwindow&#39;, bounds: {width: 500, height: 309} },
     // the create callback gets a reference to the AppWindow obj
     function(win) {
       // when the callback is executed, the DOM is loaded but no script was
       // loaded yet. So, let&#39;s attach to the load event.
       win.contentWindow.addEventListener(&#39;load&#39;, function() {
         if (readInitialState) {
           win.contentWindow.setInitialState();
         } else {
           win.contentWindow.clearInitialState();
@@ skipping 90 matching lines @@
 
 <h2 id="takeaways_">Takeaways</h2>
 
 <ul>
 <li>The event page may continue to run even when your windows are closed;
 you can move logic that is shared amoung windows to the event page.</li>
 </ul>
 
 <h2 id="you_should_also_read">You should also read</h2>
 
-<p><a href="app_lifecycle.html">Manage App Lifecycle</a> tutorial</p>
+<p><a href="app_lifecycle">Manage App Lifecycle</a> tutorial</p>
 
 <h2 id="what_39_s_next_">What's next?</h2>
 
-<p>In <a href="app_codelab7_useridentification.html">6 - Access User's Data</a>,
+<p>In <a href="app_codelab7_useridentification">6 - Access User's Data</a>,
 you will learn how to identify users and use OAuth2.0 to access Google and other third party services.</p>
 
 <p class="note"><b>Note:</b>
 The next chapter covers a still experimental API.
 If you don't want to play with experimental APIs, feel free to skip it - the
 rest of the codelab is independent from it.
 </p>