ui: add missing module docstring

gwdatafind/ui.py

@@ -16,6 +16,13 @@
 # You should have received a copy of the GNU General Public License
 # along with GWDataFind.  If not, see <http://www.gnu.org/licenses/>.
 
+"""User interface functions for GWDataFind.
+
+These are all imported to the top-level namespace, so should be
+referred to in usage as ``gwdatafind.<function>`` and not
+``gwdatafind.ui.<function>``
+"""
+
 from functools import wraps
 from re import compile as compile_regex
 from urllib.parse import urlparse