Fix links in FAQ

[wd60622]

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[wd60622]

Goal of the PR is to fix the hyperlinks on the FAQ page.

[wd60622]

Reference: https://sublime-and-sphinx-guide.readthedocs.io/en/latest/references.html#links-to-external-web-pages

[tomicapretto]

I think the failed test is because of something new in PyMC 5.5.

Btw, thanks a lot for the fix!