trailing whitespace in code fences error (#130)

Author: choldgraf

tests/test_renderers/fixtures/syntax_elements.md

@@ -139,6 +139,18 @@ foo
         foo
 .
 
+--------------------------
+Fenced Code no language with trailing whitespace:
+.
+```  
+foo
+```
+.
+<document source="notset">
+    <literal_block language="default" xml:space="preserve">
+        foo
+.
+
 --------------------------
 Image empty:
 .