Document api modules and require explicit imports of API submodules

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

@@ -16,6 +16,13 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
+"""Constraints are an advanced feature allowing you to specify parametric
+limits on properties
+
+Warning: usage of constraints are mostly untested in real life applications.
+"""
+
+from .. import wrap_usecases
 from .add_metric import add_metric
 from .add_metric_reference import add_metric_reference
 from .add_objective import add_objective
@@ -25,3 +32,5 @@ from .edit_objective import edit_objective
 from .remove_constraint import remove_constraint
 from .remove_metric import remove_metric
 from .unassign_constraint import unassign_constraint
+
+wrap_usecases(__path__, __name__)