Documentation broken for versions <v5.9.0

[lczech]

Describe the bug
This seems to be an issue in the readthedocs setup. For many tools, selecting the documentation for a wrapper earlier than Snakemake Wrappers 5.9.0 seems to break. I have tested this with a few tools:

1. For instance: https://snakemake-wrappers.readthedocs.io/en/v5.9.0/wrappers/bio/snpeff/annotate.html
2. Bottom right selector for wrapper version:
   
3. Select a version older than 5.9.0:
   
4. Page not found:
   

This is however important to look up, because for debugging my pipeline, I often need to check how exactly the wrapper that I used is implemented, and it is not always easy or even possible to upgrade without major changes.

Cheers
Lucas