There's a closed pull request on the void-packages repository

Drop sickbeard, python-cheetah, python-Markdown and remove unnecessary alternatives
https://github.com/void-linux/void-packages/pull/25660

Description:
Sickbeard is long dead. There is a fork, SickGear, that seems to be active; people can package that alternative if there is demand. This allows the removal of python-{cheetah,Markdown} and the removal of alternatives (in favor of conflicts) with the python3 equivalents.

While I was at it, I bumped python3-cheetah3.