Detect available flags for extensions (#2557)

* draft dump json in help

* polish feature

---------

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Co-authored-by: Casey Lee <cplee@nektos.com>

cmd/notices.go

@@ -20,6 +20,10 @@ type Notice struct {
 }
 
 func displayNotices(input *Input) {
+	// Avoid causing trouble parsing the json
+	if input.listOptions {
+		return
+	}
 	select {
 	case notices := <-noticesLoaded:
 		if len(notices) > 0 {