Generate functions for all API usecases for better static code features. See #2693.

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

@@ -15,3 +15,10 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+from .add_classification import add_classification
+from .add_reference import add_reference
+from .edit_classification import edit_classification
+from .edit_reference import edit_reference
+from .remove_classification import remove_classification
+from .remove_reference import remove_reference