showdown/test/issues/#523.leading-space-breaks-gfm-code-blocks.html

<pre><code class="javascript language-javascript">var test = test;
function foo() {
  return 'bar';
}
</code></pre>
<pre><code class="javascript language-javascript">var test = test;
function foo() {
  return 'bar';
}
</code></pre>
<pre><code class="javascript language-javascript">var test = test;
function foo() {
  return 'bar';
}
</code></pre>