black: Reformat with Black 23.

Black 23 enforces some slightly more specific rules about empty line
counts and redundant parenthesis removal, but the result is still
compatible with Black 22.

(This does not actually upgrade our Python environment to Black 23
yet.)

Signed-off-by: Anders Kaseorg <anders@zulip.com>
(cherry picked from commit df001db1a9)

zerver/middleware.py

@@ -532,7 +532,6 @@ class LocaleMiddleware(DjangoLocaleMiddleware):
     def process_response(
         self, request: HttpRequest, response: HttpResponseBase
     ) -> HttpResponseBase:
-
         # This is the same as the default LocaleMiddleware, minus the
         # logic that redirects 404's that lack a prefixed language in
         # the path into having a language.  See