Fix predict() docstring to label argument as locations (#125)

The `predict()` method in `DistributionEstimatorBase` takes a
`locations` argument but the docstring incorrectly labelled it as
`outcomes`.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: TomeHirata

dte_adj/base.py

@@ -464,7 +464,7 @@ def predict(
 
         Args:
             treatment_arm (int): The index of the treatment arm.
-            outcomes (np.ndarray): Scalar values to be used for computing the cumulative distribution.
+            locations (np.ndarray): Scalar values to be used for computing the cumulative distribution.
             display_progress (bool, optional): Whether to display a progress bar. Defaults to True.
 
         Returns: