refactor: replace min/max helpers with built-in min/max

We can use the built-in `min` and `max` functions since Go 1.21.

Reference: https://go.dev/ref/spec#Min_and_max
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

autopilot/simple_graph.go

@@ -85,9 +85,7 @@ func NewSimpleGraph(g ChannelGraph) (*SimpleGraph, error) {
 func maxVal(mapping map[int]uint32) uint32 {
 	maxValue := uint32(0)
 	for _, value := range mapping {
-		if maxValue < value {
-			maxValue = value
-		}
+		maxValue = max(maxValue, value)
 	}
 	return maxValue
 }

routing/unified_edges.go

@@ -6,7 +6,6 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/graph/db/models"
-	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/routing/route"
 )
@@ -379,13 +378,11 @@ func (u *edgeUnifier) getEdgeNetwork(netAmtReceived lnwire.MilliSatoshi,
 
 			capMsat = edge.policy.MaxHTLC
 		}
-		maxCapMsat = lntypes.Max(capMsat, maxCapMsat)
+		maxCapMsat = max(capMsat, maxCapMsat)
 
 		// Track the maximum time lock of all channels that are
 		// candidate for non-strict forwarding at the routing node.
-		maxTimelock = lntypes.Max(
-			maxTimelock, edge.policy.TimeLockDelta,
-		)
+		maxTimelock = max(maxTimelock, edge.policy.TimeLockDelta)
 
 		outboundFee := int64(edge.policy.ComputeFee(amt))
 		fee := outboundFee + inboundFee
@@ -440,10 +437,10 @@ func (u *edgeUnifier) getEdgeNetwork(netAmtReceived lnwire.MilliSatoshi,
 
 // minAmt returns the minimum amount that can be forwarded on this connection.
 func (u *edgeUnifier) minAmt() lnwire.MilliSatoshi {
-	min := lnwire.MaxMilliSatoshi
+	minAmount := lnwire.MaxMilliSatoshi
 	for _, edge := range u.edges {
-		min = lntypes.Min(min, edge.policy.MinHTLC)
+		minAmount = min(minAmount, edge.policy.MinHTLC)
 	}
 
-	return min
+	return minAmount
 }

watchtower/wtdb/migration4/range_index.go

@@ -74,24 +74,6 @@ func (a *RangeIndex) addRange(start, end uint64) error {
 			"than end height %d", start, end)
 	}
 
-	// min is a helper closure that will return the minimum of two uint64s.
-	min := func(a, b uint64) uint64 {
-		if a < b {
-			return a
-		}
-
-		return b
-	}
-
-	// max is a helper closure that will return the maximum of two uint64s.
-	max := func(a, b uint64) uint64 {
-		if a > b {
-			return a
-		}
-
-		return b
-	}
-
 	// Collect the ranges that fall before and after the new range along
 	// with the start and end values of the new range.
 	var before, after []rangeItem

watchtower/wtdb/migration8/range_index.go

@@ -74,24 +74,6 @@ func (a *RangeIndex) addRange(start, end uint64) error {
 			"than end height %d", start, end)
 	}
 
-	// min is a helper closure that will return the minimum of two uint64s.
-	min := func(a, b uint64) uint64 {
-		if a < b {
-			return a
-		}
-
-		return b
-	}
-
-	// max is a helper closure that will return the maximum of two uint64s.
-	max := func(a, b uint64) uint64 {
-		if a > b {
-			return a
-		}
-
-		return b
-	}
-
 	// Collect the ranges that fall before and after the new range along
 	// with the start and end values of the new range.
 	var before, after []rangeItem

watchtower/wtdb/range_index.go

@@ -74,24 +74,6 @@ func (a *RangeIndex) addRange(start, end uint64) error {
 			"than end height %d", start, end)
 	}
 
-	// min is a helper closure that will return the minimum of two uint64s.
-	min := func(a, b uint64) uint64 {
-		if a < b {
-			return a
-		}
-
-		return b
-	}
-
-	// max is a helper closure that will return the maximum of two uint64s.
-	max := func(a, b uint64) uint64 {
-		if a > b {
-			return a
-		}
-
-		return b
-	}
-
 	// Collect the ranges that fall before and after the new range along
 	// with the start and end values of the new range.
 	var before, after []rangeItem