refactor: remove incorrect logging message

Logging message claims that we ignore cancellation. That is not the case
and we handle it in both rpc.ml and the individual requests that care
about it.

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

<!-- ps-id: 3d46cda3-8ac7-4aea-8380-041a912ab1fb -->

ocaml-lsp-server/src/ocaml_lsp_server.ml

@@ -700,9 +700,7 @@ let on_notification server (notification : Client_notification.t) :
     in
     let+ () = set_diagnostics state.detached (State.diagnostics state) doc in
     state
-  | CancelRequest _ ->
-    Log.log ~section:"debug" (fun () -> Log.msg "ignoring cancellation" []);
-    Fiber.return state
+  | CancelRequest _ -> Fiber.return state
   | ChangeConfiguration req ->
     (* TODO this is wrong and we should just fetch the config from the client
        after receiving this notification *)