Upgrade black version (#7089)

stdlib/pprint.pyi

@@ -126,6 +126,7 @@ class PrettyPrinter:
             *,
             compact: bool = ...,
         ) -> None: ...
+
     def pformat(self, object: object) -> str: ...
     def pprint(self, object: object) -> None: ...
     def isreadable(self, object: object) -> bool: ...