Fix ISR, SSG and SSR learn more links

[relferreira]

Hi,

I might be wrong, but I think the "Learn More" href on the ISR, SSG and SSR pages are incorrect. It is currently linked to the "Loading UI" documentation, but I think the "Data Fetching" docs explain it better.

Thank you for this playground. It explains really well the new features of NextJS 13

[vercel[bot]]

@relferreira is attempting to deploy a commit to the Vercel Team on Vercel.

A member of the Team first needs to authorize it.

[manovotny]

@relferreira excellent catch! Thank you!