build: modernize Go usage

This commit modernizes Go usage. This was done with:

go run golang.org/x/tools/gopls/internal/analysis/modernize/cmd/modernize@latest -fix -test ./...

Then files needed to be `go fmt`ed and a few comments needed to be
restored.

The modernizations include replacing

- if/else conditional assignment by a call to the built-in min or max functions added in go1.21
- sort.Slice(x, func(i, j int) bool) { return s[i] < s[j] } by a call to slices.Sort(s), added in go1.21
- interface{} by the 'any' type added in go1.18
- append([]T(nil), s...) by slices.Clone(s) or slices.Concat(s), added in go1.21
- loop around an m[k]=v map update by a call to one of the Collect, Copy, Clone, or Insert functions from the maps package, added in go1.21
- []byte(fmt.Sprintf...) by fmt.Appendf(nil, ...), added in go1.19
- append(s[:i], s[i+1]...) by slices.Delete(s, i, i+1), added in go1.21
- a 3-clause for i := 0; i < n; i++ {} loop by for i := range n {}, added in go1.22

lib/ranges/ranges_test.go

@@ -3,6 +3,7 @@ package ranges
 import (
 	"fmt"
 	"math/rand"
+	"slices"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -139,7 +140,7 @@ func checkRanges(t *testing.T, rs Ranges, what string) bool {
 		return true
 	}
 	ok := true
-	for i := 0; i < len(rs)-1; i++ {
+	for i := range len(rs) - 1 {
 		a := rs[i]
 		b := rs[i+1]
 		if a.Pos >= b.Pos {
@@ -207,7 +208,7 @@ func TestRangeCoalesce(t *testing.T) {
 			i:    1,
 		},
 	} {
-		got := append(Ranges{}, test.rs...)
+		got := slices.Clone(test.rs)
 		got.coalesce(test.i)
 		what := fmt.Sprintf("test rs=%v, i=%d", test.rs, test.i)
 		assert.Equal(t, test.want, got, what)
@@ -224,7 +225,7 @@ func TestRangeInsert(t *testing.T) {
 		{
 			new:  Range{Pos: 1, Size: 0},
 			rs:   Ranges{},
-			want: Ranges(nil),
+			want: Ranges{},
 		},
 		{
 			new: Range{Pos: 1, Size: 1}, // .N.......
@@ -269,7 +270,7 @@ func TestRangeInsert(t *testing.T) {
 			want: Ranges{{38, 8}, {51, 12}},
 		},
 	} {
-		got := append(Ranges(nil), test.rs...)
+		got := slices.Clone(test.rs)
 		got.Insert(test.new)
 		what := fmt.Sprintf("test new=%v, rs=%v", test.new, test.rs)
 		assert.Equal(t, test.want, got, what)
@@ -279,9 +280,9 @@ func TestRangeInsert(t *testing.T) {
 }
 
 func TestRangeInsertRandom(t *testing.T) {
-	for i := 0; i < 100; i++ {
+	for range 100 {
 		var rs Ranges
-		for j := 0; j < 100; j++ {
+		for range 100 {
 			var r = Range{
 				Pos:  rand.Int63n(100),
 				Size: rand.Int63n(10) + 1,