Add enable key to logger webhook help (#14326)

This key is supported by the logger webhook config - but is not returned in the help.

internal/logger/help.go

@@ -24,6 +24,13 @@ import (
 // Help template for logger http and audit
 var (
 	Help = config.HelpKVS{
+		config.HelpKV{
+			Key:         config.Enable,
+			Description: "set to 'on' to enable the logger webhook",
+			Optional:    true,
+			Type:        "on|off",
+			Sensitive:   false,
+		},
 		config.HelpKV{
 			Key:         Endpoint,
 			Description: `HTTP(s) endpoint e.g. "http://localhost:8080/minio/logs/server"`,