dialect overflow e.g. zh-TW

We can always use split, in conjunction with `[-1]`

```ruby
def locale_country(locale)
  locale.upcase.to_s.split('-')[-1]
end
```

```irb
irb(main):001:0> 'en-US'.split('-')[-1]
=> "US"
irb(main):002:0> 'en'.split('-')[-1]
=> "en"
```