Migrate contentjson and badjson to library &

Add omitempty in format

option/rule_set.go

@@ -3,12 +3,12 @@ package option
 import (
 	"reflect"
 
-	"github.com/sagernet/sing-box/common/json"
 	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/domain"
 	E "github.com/sagernet/sing/common/exceptions"
 	F "github.com/sagernet/sing/common/format"
+	"github.com/sagernet/sing/common/json"
 
 	"go4.org/netipx"
 )
@@ -64,7 +64,7 @@ func (r *RuleSet) UnmarshalJSON(bytes []byte) error {
 	}
 	err = UnmarshallExcluded(bytes, (*_RuleSet)(r), v)
 	if err != nil {
-		return E.Cause(err, "rule set")
+		return err
 	}
 	return nil
 }
@@ -118,7 +118,7 @@ func (r *HeadlessRule) UnmarshalJSON(bytes []byte) error {
 	}
 	err = UnmarshallExcluded(bytes, (*_HeadlessRule)(r), v)
 	if err != nil {
-		return E.Cause(err, "route rule-set rule")
+		return err
 	}
 	return nil
 }
@@ -209,7 +209,7 @@ func (r *PlainRuleSetCompat) UnmarshalJSON(bytes []byte) error {
 	}
 	err = UnmarshallExcluded(bytes, (*_PlainRuleSetCompat)(r), v)
 	if err != nil {
-		return E.Cause(err, "rule set")
+		return err
 	}
 	return nil
 }