Unify doc-strings (remove type/rtype)

As this information is already provided in type hints and we don't need to maintain it in two places.

src/ifcopenshell-python/ifcopenshell/api/material/assign_profile.py

@@ -31,11 +31,8 @@ def assign_profile(
     :param material_profile: The IfcMaterialProfile to change the profile
         curve of. See ifcopenshell.api.material.add_profile to see how to
         create profiles.
-    :type material_profile: ifcopenshell.entity_instance
     :param profile: The IfcProfileDef to set the profile item's curve to.
-    :type profile: ifcopenshell.entity_instance
     :return: None
-    :rtype: None
 
     Example:
 

src/ifcopenshell-python/ifcopenshell/api/material/remove_list_item.py

@@ -29,12 +29,9 @@ def remove_list_item(
 
     :param material_list: The IfcMaterialList entity you want to remove an
         item from.
-    :type material_list: ifcopenshell.entity_instance
     :param material_index: The index of the material you want to remove from
         the list. Starts counting at 0. Defaults to 0.
-    :type material_index: int, optional
     :return: None
-    :rtype: None
 
     Example:
 

src/ifcopenshell-python/ifcopenshell/api/material/reorder_set_item.py

@@ -28,15 +28,11 @@ def reorder_set_item(
 
     :param material_set: The IfcMaterialSet which you want to reorder an
         item in.
-    :type material_set: ifcopenshell.entity_instance
     :param old_index: The index of the item you want to move. This starts
         counting from 0.
-    :type old_index: int
     :param new_index: The index of the new position the item will move to.
         This starts counting from 0.
-    :type new_index: int
     :return: None
-    :rtype: None
 
     Example: