multi: fix fmt.Errorf error wrapping

Refactor fmt.Errorf usage to correctly wrap errors instead of using
non-wrapping format verbs.

discovery/gossiper.go

@@ -1659,7 +1659,7 @@ func (d *AuthenticatedGossiper) retransmitStaleAnns(now time.Time) error {
 			chanToUpdate.info, chanToUpdate.edge,
 		)
 		if err != nil {
-			return fmt.Errorf("unable to update channel: %v", err)
+			return fmt.Errorf("unable to update channel: %w", err)
 		}
 
 		// If we have a valid announcement to transmit, then we'll send
@@ -1715,7 +1715,7 @@ func (d *AuthenticatedGossiper) retransmitStaleAnns(now time.Time) error {
 	// With all the wire announcements properly crafted, we'll broadcast
 	// our known outgoing channels to all our immediate peers.
 	if err := d.cfg.Broadcast(nil, signedUpdates...); err != nil {
-		return fmt.Errorf("unable to re-broadcast channels: %v", err)
+		return fmt.Errorf("unable to re-broadcast channels: %w", err)
 	}
 
 	return nil

discovery/gossiper_test.go

@@ -806,7 +806,7 @@ func createTestCtx(t *testing.T, startHeight uint32) (*testCtx, error) {
 	}, selfKeyDesc)
 
 	if err := gossiper.Start(); err != nil {
-		return nil, fmt.Errorf("unable to start router: %v", err)
+		return nil, fmt.Errorf("unable to start router: %w", err)
 	}
 
 	// Mark the graph as synced in order to allow the announcements to be

discovery/syncer.go

@@ -904,7 +904,7 @@ func (g *GossipSyncer) processChanRangeReply(msg *lnwire.ReplyChannelRange) erro
 		g.cfg.isStillZombieChannel,
 	)
 	if err != nil {
-		return fmt.Errorf("unable to filter chan ids: %v", err)
+		return fmt.Errorf("unable to filter chan ids: %w", err)
 	}
 
 	// As we've received the entirety of the reply, we no longer need to
@@ -1599,7 +1599,8 @@ func (g *GossipSyncer) handleSyncTransition(req *syncTransitionReq) error {
 
 	err := g.sendGossipTimestampRange(firstTimestamp, timestampRange)
 	if err != nil {
-		return fmt.Errorf("unable to send local update horizon: %v", err)
+		return fmt.Errorf("unable to send local update horizon: %w",
+			err)
 	}
 
 	g.setSyncType(req.newSyncType)

discovery/syncer_test.go

@@ -1045,7 +1045,8 @@ func TestGossipSyncerReplyChanRangeQueryBlockRange(t *testing.T) {
 	go func() {
 		for _, query := range queryReqs {
 			if err := syncer.replyChanRangeQuery(query); err != nil {
-				errCh <- fmt.Errorf("unable to issue query: %v", err)
+				errCh <- fmt.Errorf("unable to issue query: %w",
+					err)
 				return
 			}
 		}