fix tests

proc-macros/tests/ui/incorrect/rpc/rpc_empty_bounds.stderr

 error[E0277]: the trait bound `<Conf as Config>::Hash: Serialize` is not satisfied
-   --> tests/ui/incorrect/rpc/rpc_empty_bounds.rs:10:1
-    |
-10  | #[rpc(server, client, namespace = "foo", client_bounds(), server_bounds())]
-    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Serialize` is not implemented for `<Conf as Config>::Hash`
-    |
+  --> tests/ui/incorrect/rpc/rpc_empty_bounds.rs:10:1
+   |
+10 | #[rpc(server, client, namespace = "foo", client_bounds(), server_bounds())]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Serialize` is not implemented for `<Conf as Config>::Hash`
+   |
 note: required by a bound in `RpcModule::<Context>::register_method`
-   --> $WORKSPACE/core/src/server/rpc_module.rs
-    |
-    |         R: Serialize,
-    |            ^^^^^^^^^ required by this bound in `RpcModule::<Context>::register_method`
-    = note: this error originates in the attribute macro `rpc` (in Nightly builds, run with -Z macro-backtrace for more info)
+  --> $WORKSPACE/core/src/server/rpc_module.rs
+   |
+   |         R: Serialize,
+   |            ^^^^^^^^^ required by this bound in `RpcModule::<Context>::register_method`
+   = note: this error originates in the attribute macro `rpc` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `for<'de> <Conf as Config>::Hash: Deserialize<'de>` is not satisfied
   --> tests/ui/incorrect/rpc/rpc_empty_bounds.rs:10:1
@@ -17,7 +17,7 @@ error[E0277]: the trait bound `for<'de> <Conf as Config>::Hash: Deserialize<'de>
 10 | #[rpc(server, client, namespace = "foo", client_bounds(), server_bounds())]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `for<'de> Deserialize<'de>` is not implemented for `<Conf as Config>::Hash`
    |
-   = note: required because of the requirements on the impl of `DeserializeOwned` for `<Conf as Config>::Hash`
+   = note: required for `<Conf as Config>::Hash` to implement `DeserializeOwned`
 note: required by a bound in `request`
   --> $WORKSPACE/core/src/client/mod.rs
    |