(fix) highlighted-line emphasis on codeblock

[erikn69]

• Remove security message Before we have '<pre><code>THIS IS CODE</code></pre>', so, when highlight(pre);, highlightjs removes <code> as says the warning, changing to highlight(codeElement) fix it, this also happen on highlightedLine wich adds <span class="highlighted-line">

• Fix highlighted line emphasis After #547 https://github.com/highlightjs/highlight.js/wiki/security, highlightjs removes all the unescaped html, this breaks highlighted line functionality(highlightjs/740#issuecomment-1298423250) BEFORE HIGHLIGHTJS UPGRADE: This was the original functionality, the html is removed in the current version AFTER THIS FIX: It is not the same, but it emphasizes