Update black, and run auto formatting over the codebase (#9381)

 - Update black version to the latest
 - Run black auto formatting over the codebase
    - Run autoformatting according to [`docs/code_style.md
`](https://github.com/matrix-org/synapse/blob/80d6dc9783aa80886a133756028984dbf8920168/docs/code_style.md)
 - Update `code_style.md` docs around installing black to use the correct version

2 files changed, 14 insertions, 25 deletions

diff --git a/contrib/experiments/cursesio.py b/contrib/experiments/cursesio.py
index 15a22c3a0e..cff73650e6 100644
--- a/contrib/experiments/cursesio.py
+++ b/contrib/experiments/cursesio.py
@@ -63,8 +63,7 @@ class CursesStdIO:
         self.redraw()
 
     def redraw(self):
-        """ method for redisplaying lines
-            based on internal list of lines """
+        """method for redisplaying lines based on internal list of lines"""
 
         self.stdscr.clear()
         self.paintStatus(self.statusText)
diff --git a/contrib/experiments/test_messaging.py b/contrib/experiments/test_messaging.py
index d4c35ff2fc..7fbc7d8fc6 100644
--- a/contrib/experiments/test_messaging.py
+++ b/contrib/experiments/test_messaging.py
@@ -56,7 +56,7 @@ def excpetion_errback(failure):
 
 
 class InputOutput:
-    """ This is responsible for basic I/O so that a user can interact with
+    """This is responsible for basic I/O so that a user can interact with
     the example app.
     """
 
@@ -68,8 +68,7 @@ class InputOutput:
         self.server = server
 
     def on_line(self, line):
-        """ This is where we process commands.
-        """
+        """This is where we process commands."""
 
         try:
             m = re.match(r"^join (\S+)$", line)
@@ -133,7 +132,7 @@ class IOLoggerHandler(logging.Handler):
 
 
 class Room:
-    """ Used to store (in memory) the current membership state of a room, and
+    """Used to store (in memory) the current membership state of a room, and
     which home servers we should send PDUs associated with the room to.
     """
 
@@ -148,8 +147,7 @@ class Room:
         self.have_got_metadata = False
 
     def add_participant(self, participant):
-        """ Someone has joined the room
-        """
+        """Someone has joined the room"""
         self.participants.add(participant)
         self.invited.discard(participant)
 
@@ -160,14 +158,13 @@ class Room:
             self.oldest_server = server
 
     def add_invited(self, invitee):
-        """ Someone has been invited to the room
-        """
+        """Someone has been invited to the room"""
         self.invited.add(invitee)
         self.servers.add(origin_from_ucid(invitee))
 
 
 class HomeServer(ReplicationHandler):
-    """ A very basic home server implentation that allows people to join a
+    """A very basic home server implentation that allows people to join a
     room and then invite other people.
     """
 
@@ -181,8 +178,7 @@ class HomeServer(ReplicationHandler):
         self.output = output
 
     def on_receive_pdu(self, pdu):
-        """ We just received a PDU
-        """
+        """We just received a PDU"""
         pdu_type = pdu.pdu_type
 
         if pdu_type == "sy.room.message":
@@ -199,23 +195,20 @@ class HomeServer(ReplicationHandler):
             )
 
     def _on_message(self, pdu):
-        """ We received a message
-        """
+        """We received a message"""
         self.output.print_line(
             "#%s %s %s" % (pdu.context, pdu.content["sender"], pdu.content["body"])
         )
 
     def _on_join(self, context, joinee):
-        """ Someone has joined a room, either a remote user or a local user
-        """
+        """Someone has joined a room, either a remote user or a local user"""
         room = self._get_or_create_room(context)
         room.add_participant(joinee)
 
         self.output.print_line("#%s %s %s" % (context, joinee, "*** JOINED"))
 
     def _on_invite(self, origin, context, invitee):
-        """ Someone has been invited
-        """
+        """Someone has been invited"""
         room = self._get_or_create_room(context)
         room.add_invited(invitee)
 
@@ -228,8 +221,7 @@ class HomeServer(ReplicationHandler):
 
     @defer.inlineCallbacks
     def send_message(self, room_name, sender, body):
-        """ Send a message to a room!
-        """
+        """Send a message to a room!"""
         destinations = yield self.get_servers_for_context(room_name)
 
         try:
@@ -247,8 +239,7 @@ class HomeServer(ReplicationHandler):
 
     @defer.inlineCallbacks
     def join_room(self, room_name, sender, joinee):
-        """ Join a room!
-        """
+        """Join a room!"""
         self._on_join(room_name, joinee)
 
         destinations = yield self.get_servers_for_context(room_name)
@@ -269,8 +260,7 @@ class HomeServer(ReplicationHandler):
 
     @defer.inlineCallbacks
     def invite_to_room(self, room_name, sender, invitee):
-        """ Invite someone to a room!
-        """
+        """Invite someone to a room!"""
         self._on_invite(self.server_name, room_name, invitee)
 
         destinations = yield self.get_servers_for_context(room_name)