Change before_event, after_event signature to be more pythonic

[Vitalium]

Hello!

My proposal is to change signature of functions {before,after}_event from:
def before_event(event_types: Union[List[EventTypes], EventTypes]):
to:
def before_event(*event_types: EventTypes):

@before_event([Insert, Update]) vs @before_event(Insert, Update)

It looks more elegant and "pythonic" in both source and client code.

[roman-right]

Hey! This sounds reasonable. I'll try to add this today. Thank you

[roman-right]

Implemented in 1.11.12

[Vitalium]

👍 Great job! Thank you for taking into account.

By the way, typing hint for starred positional arguments can be as simple as the type of tuple entries (*args: EventTypes means args: tuple[EventTypes, ...]. But I understand that you have left list for backward compatibility.