Add StateMap type alias (#6715)

changelog.d/6715.misc

synapse/api/auth.py

synapse/events/snapshot.py

synapse/federation/sender/per_destination_queue.py

synapse/handlers/admin.py

synapse/handlers/federation.py

synapse/handlers/room.py

synapse/state/__init__.py

synapse/state/v1.py

synapse/state/v2.py

synapse/storage/data_stores/main/state.py

synapse/storage/data_stores/state/store.py

synapse/storage/state.py

synapse/types.py