Added phpdoc_separation fixer

The idea here is to go from:

```php
    /**
     * @param EngineInterface $templating
     * @return void
     */
```

to 

```php
    /**
     * @param EngineInterface $templating
     *
     * @return void
     */
```
The only difference with the next if is the usage `$type = $this->getAnnotationType($line);`
So it should be possible to optimize this and have less duplication.

Nice work so far :smile: