Update preparation_config_yaml_file.rst to include --list_sub_file ex…

…ample

docs/source/preparation_config_yaml_file.rst

@@ -147,6 +147,7 @@ Basics - Manual of writing section ``singularity_run``
 
             * See below :ref:`advanced_manual_singularity_run` --> bullet point regarding
               ``--bids-filter-file`` for explanations.
+            * See :ref:`babs-init` for examples of ``--list_sub_file``/``--list-sub-file``.
 
     * :octicon:`alert-fill` :bdg-warning:`warning` Exception for positional arguments: if you have more than one input datasets,
       you must use ``$INPUT_PATH`` to specify which dataset to use for the positional argument input BIDS dataset.