Remove .html extension from links

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

 <h1 class="page_title">Themes</h1><p>
 A <em>theme</em> is a special kind of extension
 that changes the way the browser looks.
-Themes are <a href="packaging.html">packaged</a> like regular extensions,
+Themes are <a href="packaging">packaged</a> like regular extensions,
 but they don't contain JavaScript or HTML code.
 </p>
 
 <p>
 You can find and try a bunch of themes at the
 <a href="https://chrome.google.com/webstore/category/themes">Chrome Web Store</a>.
 </p>
 
 <img src="{{static}}/images/themes-1.png"
      width="200" height="125" alt="green plants theme" />
 
 <img src="{{static}}/images/themes-2.png"
      width="200" height="125" alt="love smoke theme" />
 
 <img src="{{static}}/images/themes-3.png"
      width="200" height="125" alt="jus d'orange theme" />
 
 <h2 id="manifest"> Manifest </h2>
 <p>
 Here is an example
-<a href="manifest.html"><code>manifest.json</code></a>
+<a href="manifest"><code>manifest.json</code></a>
 file for a theme:
 </p>
 
 <pre data-filename="manifest.json">
 {
   "version": "2.6",
   "name": "camo theme",
   <b>"theme": {
     "images" : {
       "theme_frame" : "images/theme_frame_camo.png",
@@ skipping 100 matching lines @@
 
 <h2 id="moredoc"> Additional documentation </h2>
 
 <p>
 Community-written documentation to help you write themes is here:
 </p>
 
 <blockquote>
 <a href="http://code.google.com/p/chromium/wiki/ThemeCreationGuide">http://code.google.com/p/chromium/wiki/ThemeCreationGuide</a>
 </blockquote>