Update metric name

Author: Jontified

collectors/wt_client_collector.go

@@ -35,7 +35,7 @@ func NewWtClientCollector(lnd *lndclient.LndServices,
 			}, nil,
 		),
 		numPendingBackupsDesc: prometheus.NewDesc(
-			"lnd_wt_client_num_backups", "watchtower client number of backups",
+			"lnd_wt_client_num_pending_backups", "watchtower client number of pending backups",
 			[]string{
 				"tower_pubkey",
 			}, nil,