Fix typo on estimated_stepping_batches property (#19847)

Author: afspies

src/lightning/pytorch/trainer/trainer.py

@@ -1654,8 +1654,8 @@ def _results(self) -> Optional[_ResultCollection]:
     def estimated_stepping_batches(self) -> Union[int, float]:
         r"""The estimated number of batches that will ``optimizer.step()`` during training.
 
-        This accounts for gradient accumulation and the current trainer configuration. This might sets up your training
-        dataloader if hadn't been set up already.
+        This accounts for gradient accumulation and the current trainer configuration. This might be used when setting
+        up your training dataloader, if it hasn't been set up already.
 
         .. code-block:: python