docs: Use real example for EVENT_BUS_PRODUCER (#150)

openedx_events/event_bus/__init__.py

@@ -7,6 +7,8 @@
 
 - ``get_producer`` returns an ``EventBusProducer`` singleton that should be used for sending all events
   to the Event Bus. The backing implementation is chosen via the Django setting ``EVENT_BUS_PRODUCER``.
+  See for example the Kafka implementation's ``KafkaEventProducer``, with the ``create_producer`` function
+  serving as the loader: https://github.com/openedx/event-bus-kafka/blob/main/edx_event_bus_kafka/internal/producer.py
 """
 
 import warnings
@@ -97,7 +99,7 @@ def send(
 # .. setting_description: String naming a callable (function or class) that can be called to create
 #   or retrieve an instance of EventBusProducer when ``openedx_events.event_bus.get_producer`` is
 #   called. The format of the string is a dotted path to an attribute in a module, e.g.
-#   ``some.module.path.EventBusImplementation``. This producer will be managed as a singleton
+#   ``edx_event_bus_kafka.create_producer``. This producer will be managed as a singleton
 #   by openedx_events. If setting is not supplied or the callable raises an exception or does not return
 #   an instance of EventBusProducer, calls to the producer will be ignored with a warning at startup.