Port safe commits from master to polkadot-staging (#2761)

* introduce bp_messages::ChainWithMessages (#2171)

* Move Chain::ID from relay-level Chain to primitives-level Chain (#2181)

* move Chain::ID from relay-level Chain to primitives-level Chain

* removed chain IDs from bp-runtime

* add missing file header

* Some code grooming (#2276)

* some code grooming: enable warn(missing_docs) for all piblic crates + added missing documentation + removed obsolete clippy/deny workarounds

* removed strange allow + added comment related to other allow

* removed incorrect_clone_impl_on_copy_type which is unknown to CI clippy

bridges/modules/messages/src/lib.rs

@@ -33,9 +33,8 @@
 //! If this test fails with your weights, then either weights are computed incorrectly,
 //! or some benchmarks assumptions are broken for your runtime.
 
+#![warn(missing_docs)]
 #![cfg_attr(not(feature = "std"), no_std)]
-// Generated by `decl_event!`
-#![allow(clippy::unused_unit)]
 
 pub use inbound_lane::StoredInboundLaneData;
 pub use outbound_lane::StoredMessagePayload;
@@ -514,13 +513,24 @@ pub mod pallet {
 	#[pallet::generate_deposit(pub(super) fn deposit_event)]
 	pub enum Event<T: Config<I>, I: 'static = ()> {
 		/// Message has been accepted and is waiting to be delivered.
-		MessageAccepted { lane_id: LaneId, nonce: MessageNonce },
+		MessageAccepted {
+			/// Lane, which has accepted the message.
+			lane_id: LaneId,
+			/// Nonce of accepted message.
+			nonce: MessageNonce,
+		},
 		/// Messages have been received from the bridged chain.
 		MessagesReceived(
+			/// Result of received messages dispatch.
 			Vec<ReceivedMessages<<T::MessageDispatch as MessageDispatch>::DispatchLevelResult>>,
 		),
 		/// Messages in the inclusive range have been delivered to the bridged chain.
-		MessagesDelivered { lane_id: LaneId, messages: DeliveredMessages },
+		MessagesDelivered {
+			/// Lane for which the delivery has been confirmed.
+			lane_id: LaneId,
+			/// Delivered messages.
+			messages: DeliveredMessages,
+		},
 	}
 
 	#[pallet::error]