Add deprecation comment

exporter/exporterhelper/factory.go

@@ -70,6 +70,7 @@ func WithLogs(createLogsExporter CreateLogsExporter) FactoryOption {
 }
 
 // WithCustomUnmarshaler implements component.DeprecatedUnmarshaler.
+// Deprecated, use config.Unmarshal instead.
 func WithCustomUnmarshaler(customUnmarshaler component.CustomUnmarshaler) FactoryOption {
 	return func(o *factory) {
 		o.customUnmarshaler = customUnmarshaler

extension/extensionhelper/factory.go

@@ -40,6 +40,7 @@ type factory struct {
 }
 
 // WithCustomUnmarshaler implements component.DeprecatedUnmarshaler.
+// Deprecated, use config.Unmarshal instead.
 func WithCustomUnmarshaler(customUnmarshaler component.CustomUnmarshaler) FactoryOption {
 	return func(o *factory) {
 		o.customUnmarshaler = customUnmarshaler

processor/processorhelper/factory.go

@@ -50,6 +50,7 @@ type factory struct {
 }
 
 // WithCustomUnmarshaler implements component.DeprecatedUnmarshaler.
+// Deprecated, use config.Unmarshal instead.
 func WithCustomUnmarshaler(customUnmarshaler component.CustomUnmarshaler) FactoryOption {
 	return func(o *factory) {
 		o.customUnmarshaler = customUnmarshaler

receiver/receiverhelper/factory.go

@@ -29,6 +29,7 @@ import (
 type FactoryOption func(o *factory)
 
 // WithCustomUnmarshaler implements component.DeprecatedUnmarshaler.
+// Deprecated, use config.Unmarshal instead.
 func WithCustomUnmarshaler(customUnmarshaler component.CustomUnmarshaler) FactoryOption {
 	return func(o *factory) {
 		o.customUnmarshaler = customUnmarshaler