fix: improve code

Signed-off-by: Sachin Beniwal <s474996633@gmail.com>

Author: benodiwal

src/dune_lang/dune_project.ml

@@ -956,17 +956,17 @@ let parse ~dir ~(lang : Lang.Instance.t) ~file =
      and+ pkg_field =
        field_o
          "pkg"
-         (let+ loc = loc
-          and+ () = junk_everything in
-          loc)
+         (Syntax.since Stanza.syntax (3, 21)
+          >>> let+ loc = loc
+              and+ () = junk_everything in
+              loc)
      in
      (match pkg_field with
       | Some loc ->
         User_error.raise
           ~loc
-          [ Pp.text "(pkg ...) belongs in dune-workspace, not dune-project"
-          ; Pp.text "Hint: move this stanza to your dune-workspace file"
-          ]
+          ~hints:[ Pp.text "move this stanza to your dune-workspace file" ]
+          [ Pp.text "(pkg ...) belongs in dune-workspace, not dune-project" ]
       | None -> ());
      fun (opam_packages : (Loc.t * Package.t Memo.t) Package.Name.Map.t) ->
        let opam_file_location =

…s/workspaces/pkg-in-dune-project.t/run.t …st-cases/pkg/pkg-in-dune-project-error.ttest/blackbox-tests/test-cases/workspaces/pkg-in-dune-project.t/run.t renamed to test/blackbox-tests/test-cases/pkg/pkg-in-dune-project-error.t test/blackbox-tests/test-cases/workspaces/pkg-in-dune-project.t/run.t renamed to test/blackbox-tests/test-cases/pkg/pkg-in-dune-project-error.t

@@ -1,6 +1,11 @@
 Test that putting (pkg enabled) in dune-project instead of dune-workspace
 gives a helpful error message.
 
+  $ cat > dune-project <<EOF
+  > (lang dune 3.21)
+  > (pkg enabled)
+  > EOF
+
   $ dune build
   File "dune-project", line 2, characters 0-13:
   2 | (pkg enabled)