add LaTeX code sample

Author: b-kelly

docs/product/components/code-blocks.html

@@ -350,6 +350,54 @@
         </div>
     </div>
 
+    {% header "h3", "LaTeX" %}
+    <div class="stacks-preview">
+{% highlight html %}
+<pre class="s-code-block language-csharp">
+    …
+</pre>
+{% endhighlight %}
+        <div class="stacks-preview--example">
+{% highlight latex %}
+% !TeX encoding = utf8
+\documentclass{article}
+
+\usepackage[T1]{fontenc}
+\usepackage{lmodern}
+\usepackage{amsfonts}
+\usepackage{xparse}
+\usepackage{mathtools}
+
+\newcommand\hi[1]{Hello #1!}
+
+\ExplSyntaxOn
+  % Convert a roman number into an arabic one
+  \NewDocumentCommand \romantonum { m }
+    { \int_from_roman:n { #1 } }
+\ExplSyntaxOff
+
+\begin{document}
+
+\section{Highlight.js}
+\hi{you}
+This is \LaTeX\ syntax highlighted by \verb|highlight.js|.
+You should look at section~\ref{sec:fermat} next.
+
+Did you know that MDCLXI is \romantonum{MDCLXI}? % It's 1661.
+
+\subsection{Fermat}\label{sec:fermat}
+I have a wonderful proof that
+\[
+  a^n + b^n \neq c^n
+\]
+for \(a, b, c, d, n \in \mathbb{Z}_+\) with \(n > 2\).
+Sadly, it is too large to fit in this code snippet.
+
+\end{document}
+{% endhighlight %}
+        </div>
+    </div>
+
     {% header "h3", "SQL" %}
     <div class="stacks-preview">
 {% highlight html %}