Broken link in docs

[mattwthompson]

Describe the bug

The link to QCElemental docs from this page is broken

https://docs.qcarchive.molssi.org/user_guide/molecule.html

To Reproduce

Click on "the QCElemental package"

Expected behavior

The link to not go to a 404

Additional context

[bennybp]

Thanks! I've fixed it in a commit, which is part of PR #893 (which I will probably merge later this week)

The correct URLs are: https://molssi.github.io/QCElemental and https://molssi.github.io/QCElemental/model_molecule.html