标志：加号 `+` 前缀

b.Flg("warning", "w").
	Description("negatable flag: <code>--no-warning</code> is available", "").
	Group("Negatable").
	LeadingPlusSign(true). // allow `+w` parsed ok
	Default(false).
	Build()

		OnAction(func(ctx context.Context, cmd cli.Cmd, args []string) (err error) {
			wf := cmd.FlagBy("warning")
			if wf != nil && wf.LeadingPlusSign() {
				println("warning flag with leading plus sign: +w FOUND.")
			}
			return
		}).
		Build()

$ go run ./examples/leading-plus +w
warning flag with leading plus sign: +w FOUND.
$