title: Updating failed after adding shortcode
body: <p>I have created a new plugin for youtube video slider. I have used below code for plugin creation. After activating this plugin, post and page update is not working. I am getting the error is "Updating failed"</p>
  
  <p>I have used shortcode like this [az_youtube_slider] in my post.</p>
  
  <p>Can you please anyone help me to fix the error. </p>
  
  <p>Thanks in advance.</p>
  
  <pre><code>&lt;?php
  /*
  Plugin Name: Assistanz youtube slider
  Plugin URI: https://www.assistanz.com/
  Description: Get videos from youtube assistanz channel and slider
  Version: 1.0
  Author: Safia
  Author URI: https://assistanz.com/
  License: GPLv2 or later
  Text Domain: assistanz
  */
  if(!defined('ABSPATH')) exit;
  function az_youtube_slider($atts, $content = null) {
    return "&lt;p&gt;Youtube video will come here&lt;/p&gt;";
  }
  
  add_shortcode("az_youtube_slider", "az_youtube_slider");
  ?&gt;
  </code></pre>