Run gopls modernize on codebase (#34751)

Recent modernize fixes:
https://github.com/golang/tools/commits/master/gopls/internal/analysis/modernize

modules/templates/eval/eval_test.go

@@ -12,7 +12,7 @@ import (
 )
 
 func tokens(s string) (a []any) {
-	for _, v := range strings.Fields(s) {
+	for v := range strings.FieldsSeq(s) {
 		a = append(a, v)
 	}
 	return a

modules/templates/htmlrenderer.go

@@ -251,7 +251,7 @@ func extractErrorLine(code []byte, lineNum, posNum int, target string) string {
 	b := bufio.NewReader(bytes.NewReader(code))
 	var line []byte
 	var err error
-	for i := 0; i < lineNum; i++ {
+	for i := range lineNum {
 		if line, err = b.ReadBytes('\n'); err != nil {
 			if i == lineNum-1 && errors.Is(err, io.EOF) {
 				err = nil

modules/templates/scopedtmpl/scopedtmpl.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"html/template"
 	"io"
+	"maps"
 	"reflect"
 	"sync"
 	texttemplate "text/template"
@@ -40,9 +41,7 @@ func (t *ScopedTemplate) Funcs(funcMap template.FuncMap) {
 		panic("cannot add new functions to frozen template set")
 	}
 	t.all.Funcs(funcMap)
-	for k, v := range funcMap {
-		t.parseFuncs[k] = v
-	}
+	maps.Copy(t.parseFuncs, funcMap)
 }
 
 func (t *ScopedTemplate) New(name string) *template.Template {
@@ -159,9 +158,7 @@ func newScopedTemplateSet(all *template.Template, name string) (*scopedTemplateS
 
 	textTmplPtr.muFuncs.Lock()
 	ts.execFuncs = map[string]reflect.Value{}
-	for k, v := range textTmplPtr.execFuncs {
-		ts.execFuncs[k] = v
-	}
+	maps.Copy(ts.execFuncs, textTmplPtr.execFuncs)
 	textTmplPtr.muFuncs.Unlock()
 
 	var collectTemplates func(nodes []parse.Node)
@@ -220,9 +217,7 @@ func (ts *scopedTemplateSet) newExecutor(funcMap map[string]any) TemplateExecuto
 	tmpl := texttemplate.New("")
 	tmplPtr := ptr[textTemplate](tmpl)
 	tmplPtr.execFuncs = map[string]reflect.Value{}
-	for k, v := range ts.execFuncs {
-		tmplPtr.execFuncs[k] = v
-	}
+	maps.Copy(tmplPtr.execFuncs, ts.execFuncs)
 	if funcMap != nil {
 		tmpl.Funcs(funcMap)
 	}