docs: note removal of AbstractRenderer::SORT_FULL and $richSort in Kint config (#9606)

* docs: note removal of AbstractRenderer::SORT_FULL and richSort in Kint v6

* add more detailed info

* re-add Kint to the list of changed files

Author: michalsn

user_guide_src/source/installation/upgrade_460.rst

@@ -210,6 +210,8 @@ Config
     - ``Config\Feature::$strictLocaleNegotiation`` has been added.
 - app/Config/Routing.php
     - ``Config\Routing::$translateUriToCamelCase`` has been changed to ``true``.
+- app/Config/Kint.php
+    - ``Config\Kint::$richSort`` has been removed. Kint in v6 no longer uses ``AbstractRenderer::SORT_FULL``. Leaving this property in your code will cause a runtime error due to the undefined constant.
 
 All Changes
 ===========