Add missing type doc for ParamToModify

Author: softwareengineerprogrammer

src/geophires_x/Parameter.py

@@ -424,6 +424,7 @@ def default_parameter_value_message(new_val: Any, param_to_modify_name: str, def
 
 def _read_list_parameter(ParameterReadIn: ParameterEntry, ParamToModify, model) -> None:
     """
+    :type ParamToModify: :class:`~geophires_x.Parameter.Parameter`
     :type model: :class:`~geophires_x.Model.Model`
     """