DOC Add whatsnew entry for 20056 (#20966)

NicolasHug · web-flow · commit 23cf99f2ef8e · 2021-09-07T16:53:41.000+02:00
diff --git a/doc/whats_new/v1.0.rst b/doc/whats_new/v1.0.rst
@@ -713,6 +713,9 @@ Changelog
 - |Enhancement| warn only once in the main process for per-split fit failures
   in cross-validation. :pr:`20619` by :user:`Loïc Estève <lesteve>`
 
+- |Enhancement| The :class:`model_selection.BaseShuffleSplit` base class is
+  now public. :pr:`20056` by :user:`pabloduque0`.
+
 - |Fix| Avoid premature overflow in :func:`model_selection.train_test_split`.
   :pr:`20904` by :user:`Tomasz Jakubek <t-jakubek>`.
 
