tk/Cpt: fixed bug

lib/tk/cpt.ml

@@ -23,7 +23,7 @@ let of_file fn =
       )
     |> Result.all
   in
-  let cols = List.filter cols ~f:(fun (label, _) -> not (String.equal label "Site")) in
+  let cols = List.filter cols ~f:(fun (label, _) -> not (String.equal label "Sites")) in
   let nrows = match cols with
     | [] -> assert false
     | (_, h) :: _ -> Array.length h
@@ -55,6 +55,6 @@ let write_columns oc res =
 
 let to_file table ~output =
   Out_channel.with_file output ~f:(fun oc ->
-      write_row oc ("Site" :: List.map table.cols ~f:fst) ;
+      write_row oc ("Sites" :: List.map table.cols ~f:fst) ;
       write_columns oc table
     )