Notifier: The docstring for notifier.add_observer() is incomplete.

[drew2a]

The "synchronous" parameter is not documented:

tribler/src/tribler/core/utilities/notifier.py

Lines 122 to 136 in 066a904

	def add_observer(self, topic: FuncT, observer: FuncT, synchronous: Optional[bool] = None):
	""" Add the observer for the topic.
	Each callback will be added no more than once. Callbacks are called in the same order as they were added.
	topic:
	A callable which represents a "topic" to subscribe
	observer:
	A callable which will be actually called when notification is sent to the topic
	synchronous:
	A strategy of how to call the observer. If True,
	"""

[qstokkink]

The code references in this issue no longer exists and, therefore, this issue is no longer relevant.