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/state/__init__.py

@@ -398,7 +398,7 @@ class StateHandler:
     async def resolve_state_groups_for_events(
         self, room_id: str, event_ids: Iterable[str]
     ) -> _StateCacheEntry:
-        """ Given a list of event_ids this method fetches the state at each
+        """Given a list of event_ids this method fetches the state at each
         event, resolves conflicts between them and returns them.
 
         Args:
@@ -570,7 +570,9 @@ class StateResolutionHandler:
                 return cache
 
             logger.info(
-                "Resolving state for %s with groups %s", room_id, list(group_names),
+                "Resolving state for %s with groups %s",
+                room_id,
+                list(group_names),
             )
 
             state_groups_histogram.observe(len(state_groups_ids))
@@ -656,11 +658,15 @@ class StateResolutionHandler:
             return
 
         self._report_biggest(
-            lambda i: i.cpu_time, "CPU time", _biggest_room_by_cpu_counter,
+            lambda i: i.cpu_time,
+            "CPU time",
+            _biggest_room_by_cpu_counter,
         )
 
         self._report_biggest(
-            lambda i: i.db_time, "DB time", _biggest_room_by_db_counter,
+            lambda i: i.db_time,
+            "DB time",
+            _biggest_room_by_db_counter,
         )
 
         self._state_res_metrics.clear()