docs: add ListJoiner to pydoc configuration (#8821)

* docs: add ListJoiner to pydoc configuration

* Update docs/pydoc/config/joiners_api.yml

Co-authored-by: David S. Batista <[email protected]>

---------

Co-authored-by: David S. Batista <[email protected]>

Author: anakin87

docs/pydoc/config/joiners_api.yml

@@ -1,7 +1,7 @@
 loaders:
   - type: haystack_pydoc_tools.loaders.CustomPythonLoader
     search_path: [../../../haystack/components/joiners]
-    modules: ["document_joiner", "branch", "answer_joiner", "string_joiner"]
+    modules: ["answer_joiner", "branch", "document_joiner", "list_joiner", "string_joiner"]
     ignore_when_discovered: ["__init__"]
 processors:
   - type: filter