all: use Go 1.22 range-over-int

Updates #11058

Change-Id: I35e7ef9b90e83cac04ca93fd964ad00ed5b48430
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

cmd/viewer/viewer.go

@@ -149,7 +149,7 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 		}
 	}
 	writeTemplate("common")
-	for i := 0; i < t.NumFields(); i++ {
+	for i := range t.NumFields() {
 		f := t.Field(i)
 		fname := f.Name()
 		if !f.Exported() {
@@ -292,7 +292,7 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 		}
 		writeTemplate("unsupportedField")
 	}
-	for i := 0; i < typ.NumMethods(); i++ {
+	for i := range typ.NumMethods() {
 		f := typ.Method(i)
 		if !f.Exported() {
 			continue