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/offchain/src/api.rs

@@ -243,11 +243,15 @@ mod tests {
 			unimplemented!();
 		}
 
-		fn report_peer(&self, _who: PeerId, _cost_benefit: ReputationChange) {
+		fn report_peer(&self, _peer_id: PeerId, _cost_benefit: ReputationChange) {
 			unimplemented!();
 		}
 
-		fn disconnect_peer(&self, _who: PeerId, _protocol: ProtocolName) {
+		fn peer_reputation(&self, _peer_id: &PeerId) -> i32 {
+			unimplemented!()
+		}
+
+		fn disconnect_peer(&self, _peer_id: PeerId, _protocol: ProtocolName) {
 			unimplemented!();
 		}