style: Resolve clippy warnings in database and service

src/database/ser.rs

@@ -192,13 +192,13 @@ impl<W: Write> ser::Serializer for &mut Serializer<'_, W> {
 		);
 
 		match name {
-			| "Json" => serde_json::to_writer(&mut self.out, value).map_err(Into::into),
+			| "Json" => serde_json::to_writer(&mut *self.out, value).map_err(Into::into),
 			| "Cbor" => {
 				use minicbor::encode::write::Writer;
 				use minicbor_serde::Serializer;
 
 				value
-					.serialize(&mut Serializer::new(&mut Writer::new(&mut self.out)))
+					.serialize(&mut Serializer::new(&mut Writer::new(&mut *self.out)))
 					.map_err(|e| Self::Error::SerdeSer(e.to_string().into()))
 			},
 			| _ => unhandled!("Unrecognized serialization Newtype {name:?}"),

src/service/sending/mod.rs

@@ -459,21 +459,18 @@ impl Service {
 						push_key.to_owned(),
 					))
 					.await;
-
-				Ok(())
 			},
 			| (Some(appservice_id), None, None) => {
 				self.db
 					.delete_all_requests_for(&Destination::Appservice(appservice_id.to_owned()))
 					.await;
-
-				Ok(())
 			},
 			| _ => {
 				debug_warn!("cleanup_events called with too many or too few arguments");
-				Ok(())
 			},
 		}
+
+		Ok(())
 	}
 
 	fn dispatch(&self, msg: Msg) -> Result {