Missing Colon in type annotations?

Is there a missing colon in the type annotations for functions?

e.g. From the readme:

```
function main()
    :Int
    
    stuff...
end
```

Currently, `:Int` is just a symbol which gets ignored since it's not returned. Was it meant to be a return type annotation?

```
function main()::Int
    
    stuff...
end
```