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/storage/databases/main/room.py

@@ -193,8 +193,7 @@ class RoomWorkerStore(SQLBaseStore):
         )
 
     async def get_room_count(self) -> int:
-        """Retrieve the total number of rooms.
-        """
+        """Retrieve the total number of rooms."""
 
         def f(txn):
             sql = "SELECT count(*)  FROM rooms"
@@ -517,7 +516,8 @@ class RoomWorkerStore(SQLBaseStore):
             return rooms, room_count[0]
 
         return await self.db_pool.runInteraction(
-            "get_rooms_paginate", _get_rooms_paginate_txn,
+            "get_rooms_paginate",
+            _get_rooms_paginate_txn,
         )
 
     @cached(max_entries=10000)
@@ -578,7 +578,8 @@ class RoomWorkerStore(SQLBaseStore):
             return self.db_pool.cursor_to_dict(txn)
 
         ret = await self.db_pool.runInteraction(
-            "get_retention_policy_for_room", get_retention_policy_for_room_txn,
+            "get_retention_policy_for_room",
+            get_retention_policy_for_room_txn,
         )
 
         # If we don't know this room ID, ret will be None, in this case return the default
@@ -707,7 +708,10 @@ class RoomWorkerStore(SQLBaseStore):
         return local_media_mxcs, remote_media_mxcs
 
     async def quarantine_media_by_id(
-        self, server_name: str, media_id: str, quarantined_by: str,
+        self,
+        server_name: str,
+        media_id: str,
+        quarantined_by: str,
     ) -> int:
         """quarantines a single local or remote media id
 
@@ -961,7 +965,8 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
         self.config = hs.config
 
         self.db_pool.updates.register_background_update_handler(
-            "insert_room_retention", self._background_insert_retention,
+            "insert_room_retention",
+            self._background_insert_retention,
         )
 
         self.db_pool.updates.register_background_update_handler(
@@ -1033,7 +1038,8 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
                 return False
 
         end = await self.db_pool.runInteraction(
-            "insert_room_retention", _background_insert_retention_txn,
+            "insert_room_retention",
+            _background_insert_retention_txn,
         )
 
         if end:
@@ -1588,7 +1594,8 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
                 LIMIT ?
                 OFFSET ?
             """.format(
-                where_clause=where_clause, order=order,
+                where_clause=where_clause,
+                order=order,
             )
 
             args += [limit, start]