docs: fix links

[dijonkitchen]

No description provided.

[SevereOverfl0w]

The change to index.adoc doesn't look right, it says development but points to prod.

I think there's supposed to be a dev file.

[SevereOverfl0w]

Thanks for taking the time to fix these, I appreciate it.

[dijonkitchen]

There doesn't look like there is a section with same name (https://juxt.pro/edge/docs/built-in-libraries.html#lib.app.dev), so I pointed it to where the others are.

See broken link here: https://juxt.pro/edge/docs/index.html#_edge_integrated_add_ons

[SevereOverfl0w]

Had a spare minute to look at my laptop, the correct link for the dev docs is https://juxt.pro/edge/docs/lib-app-dev.html

If you don't have time/want to update that link as part of this PR, I'll pick it up in the new year.

[dijonkitchen]

Thanks, the docs are kind of confusing. Not sure where in the source that page is referencing.