chore: clarify comment

Signed-off-by: Rudi Grinberg <me@rgrinberg.com>

<!-- ps-id: f007abff-ed51-4b73-9da8-58b8b0c6d5e4 -->
Signed-off-by: Rudi Grinberg <me@rgrinberg.com>

src/dune_pkg/opam_solver.ml

@@ -558,8 +558,8 @@ let resolve_depopts ~resolve depopts =
     | Empty -> acc
     | _ ->
       (* We rely on depopts always being a list of or'ed package names. Opam
-         verifies this for us at parsing time. Dune projects have this
-         restriction for depopts and regular deps *)
+         verifies this for us at parsing time. Packages defined in dune-project
+         files have this restriction for depopts and regular deps *)
       Code_error.raise "invalid depopts" [ "depopts", Opam_dyn.filtered_formula depopts ]
   in
   OpamFormula.ors_to_list depopts