Document api modules and require explicit imports of API submodules

src/ifcopenshell-python/ifcopenshell/api/attribute/__init__.py

@@ -16,4 +16,14 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
+"""Basic modification of the attributes of an element.
+
+All IFC entities have attributes. Some of these attributes contain rules about
+inheritance and what they are allowed to contain. These usecases make sure that
+any editing complies with these rules.
+"""
+
+from .. import wrap_usecases
 from .edit_attributes import edit_attributes
+
+wrap_usecases(__path__, __name__)