engine: expose skip exception

src/alcotest-engine/core.ml

@@ -449,4 +449,6 @@ end
 module V1 = struct
   include V1_types
   module Make = Make
+
+  exception Skip = Skip
 end

src/alcotest-engine/core_intf.ml

@@ -111,7 +111,6 @@ end
 
 module type Core = sig
   exception Check_error of unit Fmt.t
-  exception Skip
 
   module V1 : sig
     module type S = V1_types.S
@@ -122,5 +121,7 @@ module type Core = sig
         [('a -> unit M.t)] within a given concurrency monad [M.t]. The [run] and
         [run_with_args] functions must be scheduled in a global event loop.
         Intended for use by the {!Alcotest_lwt} and {!Alcotest_async} backends. *)
+
+    exception Skip
   end
 end

src/alcotest-engine/test.ml

@@ -268,4 +268,4 @@ let match_raises ?here ?pos msg exnp f =
             Fmt.pf ppf "%t%a %s: got %a." (pp_location ?here ?pos) Pp.tag `Fail
               msg Fmt.exn e)
 
-let skip () = raise Core.Skip
+let skip () = raise Core.V1.Skip