Dynamically generate a heading for Extension Docs API pages

chrome/common/extensions/docs/templates/intros/proxy.html

-<p id="classSummary">
-Use the <code>chrome.proxy</code> module to manage Chrome's
-proxy settings. This module relies on the <a href="types.html#ChromeSetting">
-ChromeSetting prototype of the type API</a> for getting and setting the proxy
-configuration.
-</p>
-
 <h2 id="manifest">Manifest</h2>
 <p>You must declare the "proxy" permission
 in the <a href="manifest.html">extension manifest</a>
 to use the proxy settings API.
 For example:</p>
 <pre>{
   "name": "My extension",
   ...
   <b>"permissions": [
     "proxy"
@@ skipping 212 matching lines @@
     {'incognito': false},
     function(config) {console.log(JSON.stringify(config));});
 </pre>
 
 <p>
 Note that the <code>value</code> object passed to <code>set()</code> is not
 identical to the <code>value</code> object passed to callback function of
 <code>get()</code>. The latter will contain a
 <code>rules.proxyForHttp.port</code> element.
 </p>