Link to docs in about section returns 404

[MartinuzziFrancesco]

In the about section is linked the following docs.juliadsp.org/stable/contents/ under the package description ( Filter design, periodograms, window functions, and other digital signal processing functionality). That link returns 404

[wheeheee]

Okay, fixed. The contents page was moved to the home page and we forgot to update the link in the about section.