[4.2.x] Refs #33476 -- Applied Black's 2023 stable style.

Black 23.1.0 is released which, as the first release of the year,
introduces the 2023 stable style. This incorporates most of last year's
preview style.

https://github.com/psf/black/releases/tag/23.1.0

Backport of 097e3a70c1 from main

tests/backends/tests.py

@@ -247,7 +247,6 @@ class SequenceResetTest(TestCase):
 # This test needs to run outside of a transaction, otherwise closing the
 # connection would implicitly rollback and cause problems during teardown.
 class ConnectionCreatedSignalTest(TransactionTestCase):
-
     available_apps = []
 
     # Unfortunately with sqlite3 the in-memory test database cannot be closed,
@@ -297,7 +296,6 @@ class EscapingChecksDebug(EscapingChecks):
 
 
 class BackendTestCase(TransactionTestCase):
-
     available_apps = ["backends"]
 
     def create_squares_with_executemany(self, args):
@@ -597,7 +595,6 @@ class BackendTestCase(TransactionTestCase):
 # These tests aren't conditional because it would require differentiating
 # between MySQL+InnoDB and MySQL+MYISAM (something we currently can't do).
 class FkConstraintsTests(TransactionTestCase):
-
     available_apps = ["backends"]
 
     def setUp(self):
@@ -753,7 +750,6 @@ class FkConstraintsTests(TransactionTestCase):
 
 
 class ThreadTests(TransactionTestCase):
-
     available_apps = ["backends"]
 
     def test_default_connection_thread_local(self):