DOC Fix docstring param default value in SequentialFeatureSelector (scikit-learn#26540)

Author: jeremiedbb

sklearn/feature_selection/_sequential.py

@@ -34,7 +34,7 @@ class SequentialFeatureSelector(SelectorMixin, MetaEstimatorMixin, BaseEstimator
     estimator : estimator instance
         An unfitted estimator.
 
-    n_features_to_select : "auto", int or float, default='warn'
+    n_features_to_select : "auto", int or float, default="auto"
         If `"auto"`, the behaviour depends on the `tol` parameter:
 
         - if `tol` is not `None`, then features are selected while the score