This would probably be better (and fit with our styleguide better) as:

```ruby
EXCEPTIONAL_FORMAT_SLUGS = %w(
  check-vehicle-tax
  make-a-sorn
  register-sorn-statutory-off-road-notification
  tax-disc
  view-driving-licence
)
```

Either that or line 22 should have a trailing comma. They would both make it so when new items are added it doesn't change a line that already exists in the diff.