multi/refactor: clarify blinded payment fee rate field name

lnrpc/routerrpc/router_backend.go

@@ -490,7 +490,7 @@ func unmarshalBlindedPayment(rpcPayment *lnrpc.BlindedPaymentPath) (
 		BlindedPath:     path,
 		CltvExpiryDelta: uint16(rpcPayment.TotalCltvDelta),
 		BaseFee:         uint32(rpcPayment.BaseFeeMsat),
-		ProportionalFee: uint32(
+		ProportionalFeeRate: uint32(
 			rpcPayment.ProportionalFeeMsat,
 		),
 		HtlcMinimum: rpcPayment.HtlcMinMsat,

routing/blinding.go

@@ -36,9 +36,9 @@ type BlindedPayment struct {
 	// blinded path.
 	BaseFee uint32
 
-	// ProportionalFee is the aggregated proportional fee for payments
-	// made over the blinded path.
-	ProportionalFee uint32
+	// ProportionalFeeRate is the aggregated proportional fee rate for
+	// payments made over the blinded path.
+	ProportionalFeeRate uint32
 
 	// CltvExpiryDelta is the total expiry delta for the blinded path. Note
 	// this does not include the final cltv delta for the receiving node
@@ -122,7 +122,7 @@ func (b *BlindedPayment) toRouteHints() RouteHints {
 		MaxHTLC:       lnwire.MilliSatoshi(b.HtlcMaximum),
 		FeeBaseMSat:   lnwire.MilliSatoshi(b.BaseFee),
 		FeeProportionalMillionths: lnwire.MilliSatoshi(
-			b.ProportionalFee,
+			b.ProportionalFeeRate,
 		),
 		ToNodePubKey: func() route.Vertex {
 			return route.NewVertex(

routing/blinding_test.go

@@ -121,12 +121,12 @@ func TestBlindedPaymentToHints(t *testing.T) {
 				{},
 			},
 		},
-		BaseFee:         baseFee,
-		ProportionalFee: ppmFee,
-		CltvExpiryDelta: cltvDelta,
-		HtlcMinimum:     htlcMin,
-		HtlcMaximum:     htlcMax,
-		Features:        features,
+		BaseFee:             baseFee,
+		ProportionalFeeRate: ppmFee,
+		CltvExpiryDelta:     cltvDelta,
+		HtlcMinimum:         htlcMin,
+		HtlcMaximum:         htlcMax,
+		Features:            features,
 	}
 	require.Nil(t, blindedPayment.toRouteHints())