Small fix at documentation conf.py
Small fix at documentation conf.py

albedoweb/django-treebeard,kazmiruk/django-treebeard,velfimov/django-treebeard,kazmiruk/django-treebeard,albedoweb/django-treebeard,torchbox/django-treebeard,velfimov/django-treebeard,kazmiruk/django-treebeard,kazmiruk/django-treebeard,torchbox/django-treebeard,albedoweb/django-treebeard,albedoweb/django-treebeard,torchbox/django-treebeard,velfimov/django-treebeard,velfimov/django-treebeard