title: Add blank lines to XElement preserving other formatting
body: <p>I have an XElement that I constructed in code. It has (conceptually) 2 groups of nodes. If I just print it out, I get a nicely formatted Xml file, but with all the nodes together. If I add a couple of newlines between the 2 groups for easier human comprehension, I lose all the formatting following it.
  How can I add a small break between the 2 groups, and still keep the rest of the formatting?</p>
  
  <p><strong>Example:</strong><br>
  This is the default:</p>
  
  <pre><code>&lt;root&gt;
    &lt;node&gt;1.1&lt;/node&gt;
    &lt;node&gt;1.2&lt;/node&gt;
    &lt;node&gt;2.1&lt;/node&gt;
    &lt;node&gt;2.2&lt;/node&gt;
  &lt;/root&gt;
  </code></pre>
  
  <p>This is if I add the break:</p>
  
  <pre><code>&lt;root&gt;
    &lt;node&gt;1.1&lt;/node&gt;
    &lt;node&gt;1.2&lt;/node&gt;
  
  &lt;node&gt;2.1&lt;/node&gt;&lt;node&gt;2.2&lt;/node&gt;&lt;/root&gt;
  </code></pre>
  
  <p>This is what I want:</p>
  
  <pre><code>&lt;root&gt;
    &lt;node&gt;1.1&lt;/node&gt;
    &lt;node&gt;1.2&lt;/node&gt;
  
    &lt;node&gt;2.1&lt;/node&gt;
    &lt;node&gt;2.2&lt;/node&gt;
  &lt;/root&gt;
  </code></pre>