Upgrade black version (#7089)

stdlib/fractions.pyi

@@ -31,6 +31,7 @@ class Fraction(Rational):
     def limit_denominator(self, max_denominator: int = ...) -> Fraction: ...
     if sys.version_info >= (3, 8):
         def as_integer_ratio(self) -> tuple[int, int]: ...
+
     @property
     def numerator(self) -> int: ...
     @property