DOC update check_is_fitted what's new

Author: qinhanmin2014

doc/whats_new/v0.22.rst

@@ -71,10 +71,10 @@ Changelog
 - |Fix| :func:`utils.check_is_fitted` accepts back an explicit ``attributes``
   argument to check for specific attributes as explicit markers of a fitted
   estimator. When no explicit ``attributes`` are provided, only the attributes
-  ending with a single "_" are used as "fitted" markers. The ``all_or_any``
-  argument is also no longer deprecated. This change is made to
-  restore some backward compatibility with the behavior of this utility in
-  version 0.21. :pr:`15947` by `Thomas Fan`_.
+  that end with a underscore and do not start with double underscore are used
+  as "fitted" markers. The ``all_or_any`` argument is also no longer
+  deprecated. This change is made to restore some backward compatibility with
+  the behavior of this utility in version 0.21. :pr:`15947` by `Thomas Fan`_.
 
 .. _changes_0_22: