Support querying peer reputation (#2392)

# Description

Trivial change that resolves
https://github.com/paritytech/polkadot-sdk/issues/2185.

Since there was a mix of `who` and `peer_id` argument names nearby I
changed them all to `peer_id`.

# Checklist

- [x] My PR includes a detailed description as outlined in the
"Description" section above
- [x] My PR follows the [labeling requirements](CONTRIBUTING.md#Process)
of this project (at minimum one label for `T`
  required)
- [x] I have made corresponding changes to the documentation (if
applicable)
- [ ] I have added tests that prove my fix is effective or that my
feature works (if applicable)

---------

Co-authored-by: Bastian Köcher <git@kchr.de>

substrate/client/network/src/service/traits.rs

@@ -155,12 +155,15 @@ pub trait NetworkPeers {
 
 	/// Report a given peer as either beneficial (+) or costly (-) according to the
 	/// given scalar.
-	fn report_peer(&self, who: PeerId, cost_benefit: ReputationChange);
+	fn report_peer(&self, peer_id: PeerId, cost_benefit: ReputationChange);
+
+	/// Get peer reputation.
+	fn peer_reputation(&self, peer_id: &PeerId) -> i32;
 
 	/// Disconnect from a node as soon as possible.
 	///
 	/// This triggers the same effects as if the connection had closed itself spontaneously.
-	fn disconnect_peer(&self, who: PeerId, protocol: ProtocolName);
+	fn disconnect_peer(&self, peer_id: PeerId, protocol: ProtocolName);
 
 	/// Connect to unreserved peers and allow unreserved peers to connect for syncing purposes.
 	fn accept_unreserved_peers(&self);
@@ -254,16 +257,16 @@ where
 		T::add_known_address(self, peer_id, addr)
 	}
 
-	fn report_peer(&self, who: PeerId, cost_benefit: ReputationChange) {
-		// TODO: when we get rid of `Peerset`, we'll likely need to add some kind of async
-		// interface to `PeerStore`, otherwise we'll have trouble calling functions accepting
-		// `&mut self` via `Arc`.
-		// See https://github.com/paritytech/substrate/issues/14170.
-		T::report_peer(self, who, cost_benefit)
+	fn report_peer(&self, peer_id: PeerId, cost_benefit: ReputationChange) {
+		T::report_peer(self, peer_id, cost_benefit)
 	}
 
-	fn disconnect_peer(&self, who: PeerId, protocol: ProtocolName) {
-		T::disconnect_peer(self, who, protocol)
+	fn peer_reputation(&self, peer_id: &PeerId) -> i32 {
+		T::peer_reputation(self, peer_id)
+	}
+
+	fn disconnect_peer(&self, peer_id: PeerId, protocol: ProtocolName) {
+		T::disconnect_peer(self, peer_id, protocol)
 	}
 
 	fn accept_unreserved_peers(&self) {