fix shorten IA for new IA API

Shorten IA is currently broken (see https://duckduckgo.com/?q=shorten+https%3A%2F%2Fdylansserver.com), this fixes it.

Also should probably close this: https://duck.co/ideas/idea/1199/shortening-url-service (although I second a ddg.gg service).
It's actually best to use the `text` group, we prefer to use the `base` group only when all other templates won't suffice (e.g. something quite complex). Also, the `text` group has a "More at" by default so you won't need to explicitly enable it below