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

1 files changed, 3 insertions, 1 deletions

diff --git a/tests/handlers/test_device.py b/tests/handlers/test_device.py
index 5dfeccfeb6..821629bc38 100644
--- a/tests/handlers/test_device.py
+++ b/tests/handlers/test_device.py
@@ -260,7 +260,9 @@ class DehydrationTestCase(unittest.HomeserverTestCase):
         # Create a new login for the user and dehydrated the device
         device_id, access_token = self.get_success(
             self.registration.register_device(
-                user_id=user_id, device_id=None, initial_display_name="new device",
+                user_id=user_id,
+                device_id=None,
+                initial_display_name="new device",
             )
         )