Remove .html extension from links

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

 <h1>Network Communications</h1>
 
 <p>
 Chrome Apps can act as a network client
 for TCP and UDP connections.
 This doc shows you how to use TCP and UDP
 to send and receive data over the network.
 For more information,
 see the
-<a href="sockets_udp.html">Sockets UDP</a>,
-<a href="sockets_tcp.html">Sockets TCP</a> and
-<a href="sockets_tcp_server.html">Sockets TCP Server</a> APIs.
+<a href="sockets_udp">Sockets UDP</a>,
+<a href="sockets_tcp">Sockets TCP</a> and
+<a href="sockets_tcp_server">Sockets TCP Server</a> APIs.
 </p>
 
 <p class="note">
 <b>Note: </b>The previous version of the networking APIs ($(ref:socket)) has been
 deprecated.
 </p>
 <p></p>
 <p class="note">
 <b>API Samples: </b>
 Want to play with the code?
 Check out the
 <a href="https://github.com/GoogleChrome/chrome-app-samples/tree/master/telnet">telnet</a>
 and <a href="https://github.com/GoogleChrome/chrome-app-samples/tree/master/udp">udp</a> samples.
 </p>
 
 <h2 id="manifest">Manifest requirements</h2>
 
 <p>
 For Chrome Apps that use TCP or UDP,
-add the <a href="manifest/sockets.html">sockets</a> entry to the manifest
+add the <a href="manifest/sockets">sockets</a> entry to the manifest
 and specify the IP end point permission rules.
 For example:
 </p>
 
 <pre data-filename="manifest.json">
 "sockets": {
     "udp": {
       "send": ["host-pattern1", ...],
       "bind": ["host-pattern2", ...],
       ...
@@ skipping 13 matching lines @@
 The syntax of socket "host-pattern" entries follows these rules:
 </p>
 
 <pre>
 &lt;host-pattern> := &lt;host> | ':' &lt;port> | &lt;host> ':' &lt;port>
 &lt;host> := '*' | '*.' &lt;anychar except '/' and '*'>+
 &lt;port> := '*' | &lt;port number between 1 and 65535>)
 </pre>
 
 <p>
-See <a href="manifest/sockets.html">Sockets Manifest Key</a> for detailed
+See <a href="manifest/sockets">Sockets Manifest Key</a> for detailed
 description of the syntax.
 </p>
 
 <p>
 Examples of socket manifest entries:
 </p>
 
 <ul>
   <li><code>{ "tcp": { "connect" : "*:23" } }</code> &ndash; connecting on
    port 23 of any hosts</li>
@@ skipping 209 matching lines @@
 Call $(ref:sockets.tcp.disconnect) on the server socket ID to stop accepting
 new connections.
 </p>
 
 <pre>
 chrome.sockets.tcpServer.onAccept.removeListener(onAccept);
 chrome.sockets.tcpServer.disconnect(serverSocketId);</pre>
 
 
 <p class="backtotop"><a href="#top">Back to top</a></p>