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/owner/add_role.py

@@ -33,12 +33,9 @@ def add_role(
 
     :param assigned_object: The IfcPerson or IfcOrganization the role should
         be assigned to.
-    :type assigned_object: ifcopenshell.entity_instance
     :param role: The type of role, taken from the IFC documentation for
         IfcActorRole, or a custom name. Defaults to "ARCHITECT".
-    :type role: str, optional
     :return: The newly created IfcActorRole
-    :rtype: ifcopenshell.entity_instance
 
     Example:
 

src/ifcopenshell-python/ifcopenshell/api/owner/create_owner_history.py

@@ -61,7 +61,6 @@ def create_owner_history(file: ifcopenshell.file) -> Union[ifcopenshell.entity_i
 
     :return: The newly created IfcOwnerHistory element or `None` if it's
         not IFC2X3 and user or application is not found in the current project.
-    :rtype: Union[ifcopenshell.entity_instance, None]
 
     Example:
 

src/ifcopenshell-python/ifcopenshell/api/owner/update_owner_history.py

@@ -35,9 +35,7 @@ def update_owner_history(
 
     :param element: The IfcRoot element to update the ownership details on
         when a change is made.
-    :type element: ifcopenshell.entity_instance
     :return: The updated IfcOwnerHistory element.
-    :rtype: ifcopenshell.entity_instance
 
     Example: