Fix comment syntax.

lib/onnx/onnx.ml

@@ -12,8 +12,8 @@ module Oproto = Onnx_protoc (* Autogenerated during compilation *)
 module Oprotom = Oproto.Onnx.ModelProto
 
 type t = {
-  n_inputs : int;  (** Number of inputs. *)
-  n_outputs : int;  (** Number of outputs. *)
+  n_inputs : int;  (* Number of inputs. *)
+  n_outputs : int;  (* Number of outputs. *)
 }
 
 (* ONNX format handling. *)