Detected a unquoted template variable as an attribute. If unquoted, a malicious actor could inject custom JavaScript handlers. To fix this, add quotes around the template expression, like this: "{{ expr }}".
<pre class="code-highlight language-{{ index ($.Scratch.Get "tc-languages") $index }}"><code class="{{ index ($.Scratch.Get "tc-languages") $index }}">{{ $trimmedContent }}</code></pre>