Improve SEO for Flax

[marcvanzee]

Github Discussions doesn't always seem to work well with Flax, which means some questions that are answerable do not show up in Google search.

Here is an example: Google search for "How to count the parameters in a Flax model?" returns just the Flax Basics doc, and some unrelated questions, while we have a Github Disucssions with exactly this title: How to count the parameters in a Flax model?