Fix some spelling mistakes / typos. (#7811)

changelog.d/7811.misc

synapse/api/auth.py

synapse/config/emailconfig.py

synapse/federation/federation_client.py

synapse/federation/federation_server.py

synapse/federation/send_queue.py

synapse/federation/sender/per_destination_queue.py

synapse/federation/transport/client.py

synapse/federation/transport/server.py

synapse/notifier.py

synapse/replication/http/_base.py

synapse/replication/tcp/__init__.py

synapse/replication/tcp/commands.py

synapse/replication/tcp/protocol.py

synapse/replication/tcp/redis.py

synapse/replication/tcp/streams/events.py

synapse/streams/config.py

synapse/streams/events.py

synapse/util/__init__.py

synapse/util/async_helpers.py