Added phpdoc_separation fixer

The idea here is to go from:

```php
    /**
     * @param EngineInterface $templating
     * @return void
     */
```

to 

```php
    /**
     * @param EngineInterface $templating
     *
     * @return void
     */
```
do not override new lines here.

Just split lines into array like:
`["foo\n", "bar\n"]` or `["foo\r\n", "bar\r\n"]` or even `["foo\r\n", "bar\r", "baz\n"]`
and implode them without glue.