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/library/add_library.py

@@ -50,9 +50,7 @@ def add_library(file: ifcopenshell.file, name: str) -> ifcopenshell.entity_insta
     to a particular table and row within that database.
 
     :param name: The name of the library
-    :type name: str
     :return: The newly created IfcLibraryInformation
-    :rtype: ifcopenshell.entity_instance
 
     Example: