Issue Unit fixer , \n are removed

I have an issue with some fixers , \n are removed .
Example with this text :
```
## Verrückt und Harakiri 2
Am Tag nach dem
```
the fixer fiw the text like this
```
## Verrückt und Harakiri 2 Am Tag
```

Here the preg_match output of the regex of the fixer :

I found the problem is that \s match \n .
So to fix this we should replace \s by his equivalent minus \n .

I foud this in the python doculentation of re lib :
> When the [UNICODE](https://docs.python.org/2/library/re.html#re.UNICODE) flag is not specified, it matches any whitespace character, this is equivalent to the set [ \t\n\r\f\v]. The [LOCALE](https://docs.python.org/2/library/re.html#re.LOCALE) flag has no extra effect on matching of the space. If [UNICODE](https://docs.python.org/2/library/re.html#re.UNICODE) is set, this will match the characters [ \t\n\r\f\v] plus whatever is classified as space in the Unicode character properties database.

So replace \s by \t\r\f\v can be a solution

Start by locating the fixer and regular expression responsible for transforming the shown multiline text, then reproduce the reported \s matching behavior. Confirm that the fix preserves line breaks in the example and add or update coverage for this case; the issue does not name a specific file or test.

Written by the indexing model from the issue text.