Wrong render result when setting syntax highlight language to C#

[chengyin]

Using C# as the syntax highlight language will lead to wrong render result.

markdown = """
  ```C#
  var optional = Some(123);
  ```
  """

Earmark.as_html!(markdown)

Will produce inline code with C# in content:
<p><code class="inline">C# var optional = Some(123);</code></p>

In GitHub it renders correctly:

var optional = Some(123);

[RobertDober]

Well you should not use C#...

just kidding. Thank you for this I will try to fix this soon, hopefully low hanging fruit.