Add type hints for event streams. (#10856)

changelog.d/10856.misc

synapse/handlers/account_data.py

synapse/handlers/appservice.py

synapse/handlers/initial_sync.py

synapse/handlers/presence.py

synapse/handlers/receipts.py

synapse/handlers/room.py

synapse/handlers/sync.py

synapse/handlers/typing.py

synapse/module_api/__init__.py

synapse/notifier.py

synapse/storage/databases/main/receipts.py

synapse/streams/__init__.py

synapse/streams/events.py

tests/handlers/test_receipts.py

tests/handlers/test_typing.py

tests/rest/client/test_shadow_banned.py

tests/rest/client/test_typing.py