chore: add missing mongodb_client docstring

Author: Kolea PLESCO

src/ted_sws/notice_metadata_processor/services/metadata_normalizer.py

@@ -88,6 +88,7 @@ def extract_and_normalise_notice_metadata_from_notice(notice: Notice, mongodb_cl
 def normalise_notice(notice: Notice, mongodb_client: MongoClient = None) -> Notice:
     """
         Given a notice object, normalise metadata and return the updated object
+    :param mongodb_client:
     :param notice:
     :return:
     """