Fix rendering of code with <hlcode>

Markdown generated for <hlcode> did not conform to the Commonmark spec
and was not compatible with marked 0.6+.

Fixes arsnova#101.
Fixes GH-89.

src/main/webapp/app/view/MathJaxMarkDownPanel.js

@@ -60,7 +60,7 @@ Ext.define('ARSnova.view.MathJaxMarkDownPanel', {
 		var replaceCodeBlockFromContent = function (content) {
 			return content.replace(/<hlcode>([\s\S]*?)<\/hlcode>/g, function (element) {
 				var codeBlockMatch = element.match(/^<hlcode>\s*([\s\S]*?)\s*<\/hlcode>$/)[1];
-				return "\n```auto\n" + codeBlockMatch + "```\n";
+				return "\n```auto\n" + codeBlockMatch + "\n```\n";
 			});
 		};