make docstring more explicit about the returned content

Author: Amrou Bellalouna

pydis_site/apps/api/views.py

@@ -100,7 +100,12 @@ def _format_link(description: str, link: str, target: str) -> str:
 
     # `format` here is the result format, we have a link format here instead.
     def get(self, request, format=None):  # noqa: D102,ANN001,ANN201
-        """Returns a list of our community rules coupled with their keywords."""
+        """
+        Returns a list of our community rules coupled with their keywords.
+
+        Each item in the returned list is a tuple with the rule as first item
+        and a list of keywords that match that rules as second item.
+        """
         link_format = request.query_params.get('link_format', 'md')
         if link_format not in ('html', 'md'):
             raise ParseError(