title: Wrap a sub-string with paragraph tag in a string in content editable div
body: <p>Heres the html -:</p>
  
  <pre><code>&lt;div contenteditable="true"&gt;I am a good person&lt;/div&gt;
  </code></pre>
  
  <p>Now how to i wrap the sub-string which starts at <code>index 7 to index 17</code> with a paragraph tag, so that the result is like this -: <code>&lt;div contenteditable="true"&gt;I am a &lt;p&gt;good person&lt;/p&gt; &lt;/div&gt;</code></p>