feat(core): provide mk_eqn in CC

src/base-solver/sidekick_base_solver.ml

@@ -13,6 +13,7 @@ module Solver_arg = struct
   module Lit = Sidekick_base.Lit
 
   let cc_view = Term.cc_view
+  let mk_eqn = Term.eq
   let is_valid_literal _ = true
   module P = Proof_stub
   type proof = P.t

src/core/Sidekick_core.ml

@@ -336,6 +336,8 @@ module type CC_ARG = sig
 
   val cc_view : T.Term.t -> (T.Fun.t, T.Term.t, T.Term.t Iter.t) CC_view.t
   (** View the term through the lens of the congruence closure *)
+
+  val mk_eqn : T.Term.store -> T.Term.t -> T.Term.t -> T.Term.t
 end
 
 (** Main congruence closure signature.