Update type hint in io/formats/format.py (#57249)

* Update type hint in format.py

The brackets around the type hint broke the libcst parser. Since the brackets are not necessary for the type hint, they have been removed

* Update v2.2.1.rst

* Undo update to v2.2.1.rst

Type annotation changes are not added to change log

Author: MarkBekooy

pandas/io/formats/format.py

@@ -1546,7 +1546,7 @@ def _format_strings(self) -> list[str]:
 
 
 def format_percentiles(
-    percentiles: (np.ndarray | Sequence[float]),
+    percentiles: np.ndarray | Sequence[float],
 ) -> list[str]:
     """
     Outputs rounded and formatted percentiles.