Compose refinements

I have a (seemingly) unusual use-case with refined:

I would like to define a combination of refinements.

Here is a simple example:

```scala
import eu.timepit.refined.predicates.all._

type Hostname = NonEmptyString
type Port = PortNumber

type HostAddress = ??? // I would like this to be (NonEmptyString + ":" + PortNumber)
```

I don't think there is a way to do this in refined.
Any thoughts?