Infer generic type parameters

[klinvill]

Right now, it looks like I need to explicitly provide type parameters in ravencheck specs. For example, for a generic option (definition given below), I need to explicitly annotate the generic type everywhere it might be needed in ravencheck specifications (see the test_is_some spec below). It would be nice to instead infer this parameter when possible.

    #[define]
    pub enum Opt<T> {
        Some(T),
        None,
    }

    #[define]
    pub fn is_some<T>(opt: &Opt<T>) -> bool {
        match opt {
            Opt::<T>::Some(v) => true,
            Opt::<T>::None => false,
        }
    }

    #[verify]
    fn test_is_some<T>(v: T) -> bool {
        is_some::<T>(Opt::<T>::Some(v))
    }