fix typo

Summary: As title.

Reviewed By: tsunghsienlee

Differential Revision: D83187348

fbshipit-source-id: bea6a941aba81c1df0df2788e6aadff151e00a36

Author: wz337

distributed_shampoo/distributed_shampoo.py

@@ -1183,7 +1183,7 @@ def step(self, closure: Callable[[], float] | None = None) -> float | None:
         """Performs a single optimization step.
 
         Args:
-            closure (Callable[[], float] | Nnoe): A closure that reevaluates the model and returns the loss. (Default: None)
+            closure (Callable[[], float] | None): A closure that reevaluates the model and returns the loss. (Default: None)
 
         Returns:
             loss (float | None): The loss value returned by the closure if provided, otherwise None.