title: WordPress Gutenberg: This block contains unexpected or invalid content
body: <p>I am creating very simple text block. The block works fine when I add this for the first time. If I refresh the page and try to edit the block it show me the message "This block contains unexpected or invalid content.". I have tried to disable htmlvalidation check but that doesn't help. Also, after I click on resolve: the current block and after conversion block contain same code.</p>
  
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  <p>This is my index.js file code</p>
  
  <pre><code>&lt;pre&gt;
  /**
   * Block dependencies
   */
  import icon from './icon';
  import './style.css';
  
  /**
   * Internal block libraries
   */
  const { __ } = wp.i18n;
  const { registerBlockType } = wp.blocks;
  const { RichText } = wp.editor;
  
  
  
  
  /**
   * Register block
   */
  export default registerBlockType(
      'jsforwpblocks/richtext',
      {
          title: __('Bizbike Small Description', 'jsforwpblocks'),
          description: __('Default title', 'jsforwpblocks'),
          category: 'common',
          icon: 'text',
          keywords: [
              __('Text', 'jsforwpblocks'),
              __('Call to Action', 'jsforwpblocks'),
              __('Message', 'jsforwpblocks'),
          ],
          attributes: {
              message: {
                  type: 'array',
                  source: 'children',
                  selector: '.message-body',
              }
          },
          supports: {
              // html: false,
              className: false,
              customClassName: false,
              html: false,
              htmlValidation: false,
          },
          edit: props =&gt; {
              const { attributes: { message }, className, setAttributes } = props;
              const onChangeMessage = message =&gt; { setAttributes({ message }) };
              return (
                  &lt;div id="small-text" className={className}&gt;
                      &lt;RichText
                          tagName="div"
                          multiline="p"
                          placeholder={__('Place the title', 'jsforwpblocks')}
                          onChange={onChangeMessage}
                          value={message}
                      /&gt;
                  &lt;/div&gt;
              );
          },
          save: props =&gt; {
              const { attributes: { message } } = props;
              return (
                  &lt;div&gt;
                      &lt;div class="commute text-center"&gt;
                          {message}
                      &lt;/div&gt;
                  &lt;/div&gt;
              );
          },
      },
  );
  
  &lt;/pre&gt;
  </code></pre>