HTML is rendered when an incorrect language is specified in the code block

[salihozkara]

Describe the bug

When an incorrect or unsupported language is specified for a code block using the "Code Syntax Highlighting Plugin," the HTML content within the code block is rendered directly into the page instead of being displayed as plain text.

To Reproduce

Steps to reproduce the behavior:

1. Go to the "With All Plugins" example on the documentation site/demo.
2. Scroll down to the "Code Syntax Highlighting Plugin" section.
3. In the left-hand editor pane (the input area), enter a code block with wrong as the language specifier, but include HTML content within it. For example:

   <div id="editor" style="display:block"><span>baz</span></div>
   

4. Observe the right-hand preview pane.

Expected behavior

The HTML content within the code block should be displayed as plain text, with syntax highlighting applied if the specified language is valid and supported. It should not be rendered by the browser as live HTML.

Screenshots

Additional context

This issue affects the "Code Syntax Highlighting Plugin." Rendering arbitrary HTML from code blocks can lead to unexpected UI changes and potential security vulnerabilities if untrusted input is processed. The plugin should sanitize or escape HTML within code blocks to ensure it's displayed as text.