Docs update

Co-authored-by: Kevin Klein <7267523+kklein@users.noreply.github.com>

Author: SimonLangerQC

src/datajudge/requirements.py

@@ -1540,7 +1540,7 @@ def add_uniques_superset_constraint(
         for ``WithinRequirement``.
         By default, the null filtering does not trigger if multiple columns are fetched at once.
         It can be configured in more detail by supplying a custom ``filter_func`` function.
-        Some exemplary implementations are available in this module as ``datajudge.utils.filternull_element``,
+        Some exemplary implementations are available in this module as :func:`~datajudge.utils.filternull_element`,
         ``datajudge.utils.filternull_never``, ``datajudge.utils.filternull_element_or_tuple_all``, ``datajudge.utils.filternull_element_or_tuple_any``.
         Passing None as the argument is equivalent to ``datajudge.utils.filternull_element``, but triggers a warning.
         The deprecated default may change in future versions.