Remove .html extension from links

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

 <meta name="doc-family" content="apps">
 <h1>Create Your First App</h1>
 
 
 <p>
 This tutorial walks you through creating your first Chrome App.
 Chrome Apps are structured similarly to extensions
 so current developers will recognize the manifest and packaging methods.
 When you're done,
 you'll just need to produce a zip file of your code and assets
-in order to <a href="publish_app.html">publish</a> your app.
+in order to <a href="publish_app">publish</a> your app.
 </p>
 
 <p>
 A Chrome App contains these components:
 </p>
 
 <ul>
   <li>The <strong>manifest</strong> tells Chrome about your app, what it is,
     how to launch it and the extra permissions that it requires.</li>
   <li>The <strong>background script</strong> is used to create the event page
     responsible for managing the app life cycle.</li>
   <li>All code must be included in the Chrome App package. This includes HTML, JS, CSS
     and Native Client modules.</li>
   <li>All <strong>icons</strong> and other assets must be included
     in the package as well.</li>
 </ul>
 
 <p class="note">
 <b>API Samples: </b>
 Want to play with the code?
 Check out the
 <a href="https://github.com/GoogleChrome/chrome-app-samples/tree/master/hello-world">hello-world</a>
 sample.
 </p>
 
 <h2 id="one">Step 1: Create the manifest</h2>
 
 <p>
 First create your <code>manifest.json</code> file
-(<a href="manifest.html">Formats: Manifest Files</a>
+(<a href="manifest">Formats: Manifest Files</a>
 describes this manifest in detail):
 </p>
 
 <pre data-filename="manifest.json">
 {
   "name": "Hello World!",
   "description": "My first Chrome App.",
   "version": "0.1",
   "manifest_version": 2,
   "app": {
     "background": {
       "scripts": ["background.js"]
     }
   },
   "icons": { "16": "calculator-16.png", "128": "calculator-128.png" }
 }
 </pre>
 
 <p class="note">
 <b>Important:</b>
 Chrome Apps <b>must</b> use
-<a href="manifestVersion.html">manifest version 2</a>.
+<a href="manifestVersion">manifest version 2</a>.
 </p>
 
 <h2 id="two">Step 2: Create the background script</h2>
 
 <p>
 Next create a new file called <code>background.js</code>
 with the following content:
 </p>
 
 <pre data-filename="background.js">
 chrome.app.runtime.onLaunched.addListener(function() {
   chrome.app.window.create('window.html', {
     'bounds': {
       'width': 400,
       'height': 500
     }
   });
 });
 </pre>
 
 <p>
 In the above sample code,
-the <a href="app_lifecycle.html#lifecycle">onLaunched event</a>
+the <a href="app_lifecycle#lifecycle">onLaunched event</a>
 will be fired when the user starts the app.
 It then immediately opens a window for the app of the specified width and height.
 Your background script may contain additional listeners,
 windows, post messages, and launch data,
 all of which are used by the event page to manage the app.
 </p>
 
 <h2 id="three">Step 3: Create a window page</h2>
 
 <p>
@@ skipping 82 matching lines @@
   </li>
   <li>
     <code>--app-id=ajjhbohkjpincjgiieeomimlgnll</code> launches an app
     already loaded into Chrome. It does not restart any previously running
     app, but it does launch the new app with any updated content.
   </li>
 </ul>
 </p>
 
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