Add IPv4 address column to output table

- Added IPv4 endpoint address as a new column in the results table
- Adjusted column formatting to accommodate the new 15-character wide column
- Makes it easier to see which IP addresses correspond to each relay

cmd/mullvadclosest/main.go

@@ -186,13 +186,14 @@ func PrintRelayLatencies(relayLatencies []RelayLatency, totalRelays int, deadRel
 		fmt.Println()
 	}
 
-	fmt.Printf("%-20s %-20s %-30s %s\n", "Country", "City", "Hostname", "Latency")
+	fmt.Printf("%-20s %-20s %-30s %-15s %s\n", "Country", "City", "Hostname", "IPv4 Address", "Latency")
 	for i, rl := range relayLatencies {
 		if i < 25 || i >= len(relayLatencies)-4 {
-			fmt.Printf("%-20s %-20s %-30s %v\n",
+			fmt.Printf("%-20s %-20s %-30s %-15s %v\n",
 				rl.Relay.Location.Country,
 				rl.Relay.Location.City,
 				rl.Relay.Hostname,
+				rl.Relay.Ipv4AddrIn,
 				rl.Latency)
 		}
 		if i == 24 {