Fix ActiveTab sample extension (extension version in manifest needs to be a string).

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

 <style>
   #active-tab-images {
     margin-top: 1em;
   }
   #active-tab-images tr {
     vertical-align: top;
   }
   #active-tab-images .spacing {
     width: 1em;
   }
@@ skipping 30 matching lines @@
 
 <h2 id="example">Example</h2>
 
 <h3 id="manifest.json">manifest.json</h3>
 
 <p>
 <pre>
 {
   "manifest_version": 2,
   "name": "Page Redder",
-  "version": 1,
+  "version": "1.0",
   <b>"permissions": ["activeTab"]</b>,
   "browser_action": {},
   "background": {
     "scripts": ["background.js"],
     "persistent": false
   }
 }
 </pre>
 </p>
 
@@ skipping 37 matching lines @@
 <p>
 The following user gestures enable <code>activeTab</code>:
 <ul>
   <li>Executing a <a href="browserAction.html">browser action</a>
   <li>Executing a <a href="pageAction.html">page action</a>
   <li>Executing a <a href="contextMenus.html">context menu item</a>
   <li>Executing a keyboard shortcut from the <a href="commands.html">commands API</a>
   <li>Accepting a suggestion from the <a href="omnibox.html">omnibox API</a>
 </ul>
 </p>