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/federation/send_queue.py

@@ -468,8 +468,7 @@ class KeyedEduRow(
 
 
 class EduRow(BaseFederationRow, namedtuple("EduRow", ("edu",))):  # Edu
-    """Streams EDUs that don't have keys. See KeyedEduRow
-    """
+    """Streams EDUs that don't have keys. See KeyedEduRow"""
 
     TypeId = "e"
 
@@ -519,7 +518,10 @@ def process_rows_for_federation(transaction_queue, rows):
     # them into the appropriate collection and then send them off.
 
     buff = ParsedFederationStreamData(
-        presence=[], presence_destinations=[], keyed_edus={}, edus={},
+        presence=[],
+        presence_destinations=[],
+        keyed_edus={},
+        edus={},
     )
 
     # Parse the rows in the stream and add to the buffer