Remove .html extension from links

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

 <h1>Packaged Apps</h1>
 
 
 <p class="warning">
 <b>Warning: </b>
 All content in this doc refers to the legacy version of packaged apps.
 Your legacy packaged apps will still work,
 but you won't have access to any of the new APIs.
 Check out the new version of
-<a href="../apps/about_apps.html">Chrome Apps</a>;
+<a href="../apps/about_apps">Chrome Apps</a>;
 otherwise, you're missing out!
 </p>
 
 <p>
 This page talks about packaged apps&mdash;how
 you implement them,
 and how they're different from
 extensions and ordinary web apps.
 </p>
 
 <h2 id="overview">Overview</h2>
 
 <p>
 A packaged app is a web app
 that's bundled into a <code>.crx</code> file
 and can use Chrome extension features.
 You build a packaged app just like you build an extension,
 except that a packaged app can't include a
-<a href="browserAction.html">browser action</a> or
-<a href="pageAction.html">page action</a>.
+<a href="browserAction">browser action</a> or
+<a href="pageAction">page action</a>.
 Instead, a packaged app includes at least one HTML file
 within its <code>.crx</code> file
 that provides the app's user interface.
 </p>
 
 <p>
 Packaged apps are a type of
 <a href="http://code.google.com/chrome/apps/">installable web app</a>&mdash;a
 web app that can be installed in Chrome.
 The other type of installable web app is a
-<a href="http://code.google.com/chrome/apps/docs/developers_guide.html">hosted app</a>,
+<a href="http://code.google.com/chrome/apps/docs/developers_guide">hosted app</a>,
 which is an ordinary web app with a bit of additional metadata.
 </p>
 
 <p>
 If you're developing a web app for the Chrome Web Store,
 you might want to use a packaged app
 instead of a hosted app if any of the following are true:
 </p>
 
 <ul>
@@ skipping 99 matching lines @@
   </dd>
 </dl>
 
 <p>
 Packaged apps usually provide a 16x16 icon
 to be used as the favicon for
 tabs that contain app's pages.
 They also should provide a 128x128 icon,
 but not a 48x48 icon.
 See the manifest documentation for the
-<a href="manifest/icons.html">"icons" field</a>
+<a href="manifest/icons">"icons" field</a>
 for more information.
 </p>
 
 <p>
 For further details on what a packaged app's manifest can contain, see the
-<a href="manifest.html">manifest documentation</a>.
+<a href="manifest">manifest documentation</a>.
 </p>
 
 <h2 id="next">What next?</h2>
 
 <p>
-Read the <a href="overview.html">Overview</a> to learn
+Read the <a href="overview">Overview</a> to learn
 basic concepts about extensions.
 </p>
 
 <p class="backtotop"><a href="#top">Back to top</a></p>