Run gopls modernize on codebase (#34751)

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

modules/auth/password/password.go

@@ -101,7 +101,7 @@ func Generate(n int) (string, error) {
 	buffer := make([]byte, n)
 	maxInt := big.NewInt(int64(len(validChars)))
 	for {
-		for j := 0; j < n; j++ {
+		for j := range n {
 			rnd, err := rand.Int(rand.Reader, maxInt)
 			if err != nil {
 				return "", err

modules/auth/password/password_test.go

@@ -50,7 +50,7 @@ func TestComplexity_Generate(t *testing.T) {
 
 	test := func(t *testing.T, modes []string) {
 		testComplextity(modes)
-		for i := 0; i < maxCount; i++ {
+		for range maxCount {
 			pwd, err := Generate(pwdLen)
 			assert.NoError(t, err)
 			assert.Len(t, pwd, pwdLen)

modules/auth/password/pwn/pwn.go

@@ -101,7 +101,7 @@ func (c *Client) CheckPassword(pw string, padding bool) (int, error) {
 	}
 	defer resp.Body.Close()
 
-	for _, pair := range strings.Split(string(body), "\n") {
+	for pair := range strings.SplitSeq(string(body), "\n") {
 		parts := strings.Split(pair, ":")
 		if len(parts) != 2 {
 			continue