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, 4 insertions, 1 deletions

diff --git a/tests/test_server.py b/tests/test_server.py

index 815da18e65..55cde7f62f 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -166,7 +166,10 @@ class JsonResourceTests(unittest.TestCase):
 
         res = JsonResource(self.homeserver)
         res.register_paths(
-            "GET", [re.compile("^/_matrix/foo$")], _callback, "test_servlet",
+            "GET",
+            [re.compile("^/_matrix/foo$")],
+            _callback,
+            "test_servlet",
         )
 
         # The path was registered as GET, but this is a HEAD request.