Revert "turn canonical structures that don't have any instances into plain records"

This reverts commit 7266d16b

algebra/functor.v

@@ -2,7 +2,7 @@ From algebra Require Export cmra.
 
 (** * Functors from COFE to CMRA *)
 (* TODO RJ: Maybe find a better name for this? It is not PL-specific any more. *)
-Record iFunctor := IFunctor {
+Structure iFunctor := IFunctor {
   ifunctor_car :> cofeT → cmraT;
   ifunctor_map {A B} (f : A -n> B) : ifunctor_car A -n> ifunctor_car B;
   ifunctor_map_ne {A B} n : Proper (dist n ==> dist n) (@ifunctor_map A B);

algebra/sts.v

@@ -7,7 +7,7 @@ Local Arguments unit _ _ !_ /.
 
 (** * Definition of STSs *)
 Module sts.
-Record stsT := STS {
+Structure stsT := STS {
   state : Type;
   token : Type;
   prim_step : relation state;