Improve "no shipping rates" message.

Done, please review!

Thanks @Grevil, I agree that this is currently a bit confusing. Would be even better to also adjust the Drupal form message (empty required field) if no shipping method matches.

Maybe we should even allow defining a configurable fallback message for that case as a setting, so that shop owners can explain the potential reasons in this case instead of a hard-coded message?

Let's wait for Centarro feedback on that.

Regarding the class: I think it would make sense to add a context class like you did, and also add a Drupal error or warning message class to show the message appropriately by default.

I'm unsure if such a class exists, or if that means we'd have to use something like the message's markup?

@jsacksick what are your thoughts here?

Closed in favor of ✨ Use a theme function for rendering "there is no shipping rate" Needs review .