Correct tag trimming

[aausch]

fixing a bug with tag trimming which leads to incorrect indentation for some code blocks.

currently, when this is put inside of a codeblock:

    return result;
  }
  if (tired && night){
    sleep();
  }

it will incorrectly be rendered as (approximately, can't reproduce the exact error with the github editor):

return result;
  }
  if (tired && night){
    sleep();
  }

[Xuanwo]

wonderful work!