Fix broken links in SSR documentation

[sina-ss]

This PR fixes several broken links in the SSR documentation (ssr.md) that were preventing proper navigation between related concepts.

• Fixed link to "prefetching" documentation
• Fixed link to "request-waterfalls" documentation
• Fixed link to "dependent-queries" documentation
• Fixed section-specific link to "prefetching#dependent-queries--code-splitting"

[sina-ss]

This problem also exists in some other pages of the documentation. Write me a comment so I can add it to the pull request and fix other issues if needed.

[TkDodo]

I remember ./ links didn’t work in the past for whatever reason. We’ll see after merging I guess

[TkDodo]

yeah the links are still broken. They now go from:

https://tanstack.com/query/v5/docs/framework/react/guides/ssr

to:

https://tanstack.com/query/v5/docs/framework/react/guides/ssr/prefetching

which doesn’t exist.

I think what we want here is links to point to ../guides/prefetching to make it work.