random line shown as bold, but shouldn't
when writigin 'word1 RETURN SPACE word2', word1 shows as bold, eg:

![image](https://user-images.githubusercontent.com/2194784/42663760-d8ef2b9c-85eb-11e8-8305-e7d7d199492a.png)
(from https://forum.nim-lang.org/t/4037#25141 before I changed it to remove the RETURN+ SPACE)
```
before
 after 
```

this is not documented in https://forum.nim-lang.org/about/rst (and searching for "bold" under http://docutils.sourceforge.net/docs/user/rst/quickref.html doesn't show anything either)
