Confusion in settings block after routers
This code doesn't work:

```nim
import asyncdispatch, jester

router api:
  get "/":
    resp Http200, "hi"

settings:
  port = Port(9001)

routes:
  extend api, "/api"
```

but this code does:

```nim
import asyncdispatch, jester

settings:
  port = Port(9001)

router api:
  get "/":
    resp Http200, "hi"

routes:
  extend api, "/api"
```