Function build_synthesis_constraint 

pub fn build_synthesis_constraint(
    spec_type: &Term,
    config: &SynthesisConstraintConfig,
) -> SynthesisConstraint

Convert a kernel Pi-typed specification into a synthesis constraint.

Given a spec like Pi(a:Bit). Pi(b:Bit). Bit, this determines whether the spec can be synthesized by:

1. Extracting input/output types
2. Checking all types are hardware types (Bit, BVec, Unit)
3. Returning Satisfiable if the spec is well-formed