title: Add prefix to XML root node
body: <p>I am using Nokogiri to generate XML. I would like to add a namespace prefix to the XML root node only but the problem is applying the prefix to the first element it get apply to all children elements.</p>
  
  <p>This is my expected result:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;req:Request xmlns:req="http://www.google.com" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" schemaVersion="1.0"&gt;
   &lt;LanguageCode&gt;en&lt;/LanguageCode&gt;
   &lt;Enabled&gt;Y&lt;/Enabled&gt;
  &lt;/req:Request&gt;
  </code></pre>