fix(cli/help): show deprecation notice properly for flags (#7904)

cli/help.go

@@ -135,6 +135,31 @@ var usageTemplate = template.Must(
 			"isDeprecated": func(opt clibase.Option) bool {
 				return len(opt.UseInstead) > 0
 			},
+			"useInstead": func(opt clibase.Option) string {
+				var sb strings.Builder
+				for i, s := range opt.UseInstead {
+					if i > 0 {
+						if i == len(opt.UseInstead)-1 {
+							_, _ = sb.WriteString(" and ")
+						} else {
+							_, _ = sb.WriteString(", ")
+						}
+					}
+					if s.Flag != "" {
+						_, _ = sb.WriteString("--")
+						_, _ = sb.WriteString(s.Flag)
+					} else if s.FlagShorthand != "" {
+						_, _ = sb.WriteString("-")
+						_, _ = sb.WriteString(s.FlagShorthand)
+					} else if s.Env != "" {
+						_, _ = sb.WriteString("$")
+						_, _ = sb.WriteString(s.Env)
+					} else {
+						_, _ = sb.WriteString(s.Name)
+					}
+				}
+				return sb.String()
+			},
 			"formatLong": func(long string) string {
 				// We intentionally don't wrap here because it would misformat
 				// examples, where the new line would start without the prior