Adding documentation for extensions options pages.

chrome/common/extensions/docs/static/manifest.html

 <div id="pageData-title" class="pageData">Formats: Manifest Files</div>
 <div id="pageData-showTOC" class="pageData">true</div>
 
 <p>
 Every extension has a
 <a href="http://www.json.org">JSON</a>-formatted manifest file,
 named <code>manifest.json</code>,
 that provides important information about the extension.
 </p>
 
@@ skipping 16 matching lines @@
   "<a href="autoupdate.html">update_url</a>": "http://<em>path/to/updateInfo</em>.xml",
 
   "<a href="background_pages.html">background_page</a>": "<em>aFile</em>.html",
   "<a href="browserAction.html">brower_action</a>": {...},
   "<a href="ntp.html">chrome_url_overrides</a>": {...},
   "<a href="content_scripts.html">content_scripts</a>": [...],
   "<a href="pageAction.html">page_action</a>": {...},
   "<a href="#permissions">permissions</a>": [...],
   "<a href="npapi.html">plugins</a>": [...],
   "<a href="themes.html">theme</a>": {...},
-  "<a href="toolstrip.html">toolstrips</a>": [...]
+  "<a href="toolstrip.html">toolstrips</a>": [...],
+  "<a href="options.html">options_page</a>": "<em>aFile</em>.html",
 }
 </pre>
 
 
 <h2>Field details</h2>
 
 <p>
 This section covers fields that aren't described in another page.
 For a complete list of fields,
 with links to where they're described in detail,
@@ skipping 82 matching lines @@
 </pre>
 
 <p>
 For more information, see
 <a href="xhr.html">Cross-Origin XMLHttpRequest</a>,
 <a href="windows.html">Windows</a>,
 <a href="tabs.html">Tabs</a>, and
 <a href="bookmarks.html">Bookmarks</a>.
 </p>