Add final keyword

When a class is declared final and has a namespace then the class braces are incorrectly indented:

```php
<?php
/**
 * Braces are incorrectly indented
 */
namespace Test;

final class One
{
}
```

to


```php
<?php
/**
 * Braces are incorrectly indented
 */
namespace Test;

final class One
    {
    }
```

Adding final to block start seems to be the way to fix it.