multi: fix most obvious linter errors

cmd/loop/loopin.go

@@ -41,8 +41,7 @@ func loopIn(ctx *cli.Context) error {
 		args = args.Tail()
 	default:
 		// Show command help if no arguments and flags were provided.
-		cli.ShowCommandHelp(ctx, "in")
-		return nil
+		return cli.ShowCommandHelp(ctx, "in")
 	}
 
 	amt, err := parseAmt(amtStr)

cmd/loop/loopout.go

@@ -59,8 +59,7 @@ func loopOut(ctx *cli.Context) error {
 		args = args.Tail()
 	default:
 		// Show command help if no arguments and flags were provided.
-		cli.ShowCommandHelp(ctx, "out")
-		return nil
+		return cli.ShowCommandHelp(ctx, "out")
 	}
 
 	amt, err := parseAmt(amtStr)

cmd/loop/main.go

@@ -97,7 +97,7 @@ type limits struct {
 }
 
 func getLimits(amt btcutil.Amount, quote *looprpc.QuoteResponse) *limits {
-	maxSwapRoutingFee := getMaxRoutingFee(btcutil.Amount(amt))
+	maxSwapRoutingFee := getMaxRoutingFee(amt)
 	maxPrepayRoutingFee := getMaxRoutingFee(btcutil.Amount(
 		quote.PrepayAmt,
 	))
@@ -126,7 +126,7 @@ func displayLimits(swapType loop.Type, amt btcutil.Amount, l *limits,
 	if l.maxPrepayRoutingFee != nil {
 		totalSuccessMax += *l.maxPrepayRoutingFee
 	}
-	
+
 	if swapType == loop.TypeIn && externalHtlc {
 		fmt.Printf("On-chain fee for external loop in is not " +
 			"included.\nSufficient fees will need to be paid " +
@@ -135,7 +135,7 @@ func displayLimits(swapType loop.Type, amt btcutil.Amount, l *limits,
 	}
 
 	fmt.Printf("Max swap fees for %d Loop %v: %d\n",
-		btcutil.Amount(amt), swapType, totalSuccessMax,
+		amt, swapType, totalSuccessMax,
 	)
 
 	fmt.Printf("CONTINUE SWAP? (y/n), expand fee detail (x): ")

cmd/loop/quote.go

@@ -28,8 +28,7 @@ func quote(ctx *cli.Context) error {
 	// Show command help if the incorrect number arguments and/or flags were
 	// provided.
 	if ctx.NArg() != 1 || ctx.NumFlags() > 1 {
-		cli.ShowCommandHelp(ctx, "quote")
-		return nil
+		return cli.ShowCommandHelp(ctx, "quote")
 	}
 
 	args := ctx.Args()