Pass str to twisted's IReactorTCP (#10895)

This follows a correction made in twisted/twisted#1664 and should fix our Twisted Trial CI job.

Until that change is in a twisted release, we'll have to ignore the type
of the `host` argument. I've raised #10899 to remind us to review the
issue in a few months' time.

synapse/replication/tcp/handler.py

@@ -315,7 +315,7 @@ class ReplicationCommandHandler:
                 hs, outbound_redis_connection
             )
             hs.get_reactor().connectTCP(
-                hs.config.redis.redis_host.encode(),
+                hs.config.redis.redis_host,  # type: ignore[arg-type]
                 hs.config.redis.redis_port,
                 self._factory,
             )
@@ -324,7 +324,11 @@ class ReplicationCommandHandler:
             self._factory = DirectTcpReplicationClientFactory(hs, client_name, self)
             host = hs.config.worker.worker_replication_host
             port = hs.config.worker.worker_replication_port
-            hs.get_reactor().connectTCP(host.encode(), port, self._factory)
+            hs.get_reactor().connectTCP(
+                host,  # type: ignore[arg-type]
+                port,
+                self._factory,
+            )
 
     def get_streams(self) -> Dict[str, Stream]:
         """Get a map from stream name to all streams."""

synapse/replication/tcp/redis.py

@@ -364,6 +364,12 @@ def lazyConnection(
     factory.continueTrying = reconnect
 
     reactor = hs.get_reactor()
-    reactor.connectTCP(host.encode(), port, factory, timeout=30, bindAddress=None)
+    reactor.connectTCP(
+        host,  # type: ignore[arg-type]
+        port,
+        factory,
+        timeout=30,
+        bindAddress=None,
+    )
 
     return factory.handler