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
`](80d6dc9783/docs/code_style.md)
 - Update `code_style.md` docs around installing black to use the correct version

synapse/handlers/room.py

@@ -198,7 +198,9 @@ class RoomCreationHandler(BaseHandler):
         if r is None:
             raise NotFoundError("Unknown room id %s" % (old_room_id,))
         new_room_id = await self._generate_room_id(
-            creator_id=user_id, is_public=r["is_public"], room_version=new_version,
+            creator_id=user_id,
+            is_public=r["is_public"],
+            room_version=new_version,
         )
 
         logger.info("Creating new room %s to replace %s", new_room_id, old_room_id)
@@ -236,7 +238,9 @@ class RoomCreationHandler(BaseHandler):
 
         # now send the tombstone
         await self.event_creation_handler.handle_new_client_event(
-            requester=requester, event=tombstone_event, context=tombstone_context,
+            requester=requester,
+            event=tombstone_event,
+            context=tombstone_context,
         )
 
         old_room_state = await tombstone_context.get_current_state_ids()
@@ -257,7 +261,10 @@ class RoomCreationHandler(BaseHandler):
         # finally, shut down the PLs in the old room, and update them in the new
         # room.
         await self._update_upgraded_room_pls(
-            requester, old_room_id, new_room_id, old_room_state,
+            requester,
+            old_room_id,
+            new_room_id,
+            old_room_state,
         )
 
         return new_room_id
@@ -570,7 +577,7 @@ class RoomCreationHandler(BaseHandler):
         ratelimit: bool = True,
         creator_join_profile: Optional[JsonDict] = None,
     ) -> Tuple[dict, int]:
-        """ Creates a new room.
+        """Creates a new room.
 
         Args:
             requester:
@@ -691,7 +698,9 @@ class RoomCreationHandler(BaseHandler):
         is_public = visibility == "public"
 
         room_id = await self._generate_room_id(
-            creator_id=user_id, is_public=is_public, room_version=room_version,
+            creator_id=user_id,
+            is_public=is_public,
+            room_version=room_version,
         )
 
         # Check whether this visibility value is blocked by a third party module
@@ -884,7 +893,10 @@ class RoomCreationHandler(BaseHandler):
                 _,
                 last_stream_id,
             ) = await self.event_creation_handler.create_and_send_nonmember_event(
-                creator, event, ratelimit=False, ignore_shadow_ban=True,
+                creator,
+                event,
+                ratelimit=False,
+                ignore_shadow_ban=True,
             )
             return last_stream_id
 
@@ -984,7 +996,10 @@ class RoomCreationHandler(BaseHandler):
         return last_sent_stream_id
 
     async def _generate_room_id(
-        self, creator_id: str, is_public: bool, room_version: RoomVersion,
+        self,
+        creator_id: str,
+        is_public: bool,
+        room_version: RoomVersion,
     ):
         # autogen room IDs and try to create it. We may clash, so just
         # try a few times till one goes through, giving up eventually.