DOC More precise doc for change of default value of a parameter
@@ -1208,9 +1208,17 @@ When the change is in a class, we validate and raise warning in ``fit``::
Similar to deprecations, the warning message should always give both the
version in which the change happened and the version in which the old behavior
-will be removed. The docstring needs to be updated accordingly. We need a test
-which ensures that the warning is raised in relevant cases but not in other
-cases. The warning should be caught in all other tests
+will be removed.
+
+The parameter description in the docstring needs to be updated accordingly by adding
+a `versionchanged` directive with the old and new default value, pointing to the
+version when the change will be effective::
+
+ .. versionchanged:: 0.22
+ The default value for `n_clusters` will change from 5 to 10 in version 0.22.
+
+Finally, we need a test which ensures that the warning is raised in relevant cases but
+not in other cases. The warning should be caught in all other tests
(using e.g., ``@pytest.mark.filterwarnings``), and there should be no warning
in the examples.
