Rename GenericProto to Notifications (#8415)

* Rename GenericProto to Notifications

* Small comment fix

substrate/client/network/src/protocol/notifications.rs

@@ -0,0 +1,28 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Implementation of libp2p's `NetworkBehaviour` trait that establishes communications and opens
+//! notifications substreams.
+
+pub use self::behaviour::{Notifications, NotificationsOut};
+pub use self::handler::{NotifsHandlerError, NotificationsSink, Ready};
+
+mod behaviour;
+mod handler;
+mod upgrade;
+mod tests;