Dagger's syntax when calling functions with kwards does not match Julia syntax

Consider the following Julia function:
```
f(a; b) = a + b
@assert f(1, b=2) === f(1; b=2)   # can be called with either `,` or `;`
```
Now let us try to call it with Dagger:
```
julia> fetch( Dagger.@spawn f(1; b=2) )
3

julia> fetch( Dagger.@spawn f(1, b=2) )
ERROR: MethodError: no method matching tuple(::Int64; b::Int64)
```