Update CHANGELOG.md

Clarified changelog entry

Author: sliverc

CHANGELOG.md

@@ -13,7 +13,10 @@ any parts of the framework not mentioned in the documentation should generally b
 ### Added
 
 * Ability for the user to select `included_serializers` to apply when using `BrowsableAPI`, based on available `included_serializers` defined for the current endpoint.
-* Fixed #859: Allow users to overwrite a view's `get_serializer()` and `get_serializer_class()` methods for views that have related fields.
+
+### Fixed
+
+* Allow users to overwrite a view's `get_serializer_class()` method when using [related urls](https://django-rest-framework-json-api.readthedocs.io/en/stable/usage.html#related-urls)
 
 
 ## [4.0.0] - 2020-10-31