fix: HTML code blocks not wrapped in <pre>...</pre>

This bug was introduced with commit #51e2b655af43f36bc2fd3e9c369dbd48046d2de6.

Author: gennaroprota

share/mrdocs/addons/generator/html/partials/doc/block/code.html.hbs

@@ -1,3 +1,3 @@
-<code class="language-{{ or info "cpp" }}">
+<pre><code class="language-{{ or info "cpp" }}">
 {{{ replace (replace (replace literal "&" "&amp;") ">" "&gt;") "<" "&lt;" }}}
-</code>
+</code></pre>