Fix colon in comment

Fixed scenario when auto indent has been applied after `:` in comment block

before:
![before](https://cloud.githubusercontent.com/assets/4076929/5367130/95b84d0a-7ff9-11e4-803c-2053a0aab443.gif)

after:
![after](https://cloud.githubusercontent.com/assets/4076929/5367132/9ba0f3de-7ff9-11e4-9cfb-5fbffccbbf98.gif)