docs: Fix same-page anchor links that don't scroll to target (#11989)
## Summary
- Same-page anchor links using full paths (e.g.
`/docs/crafting-your-repository/caching#task-inputs`) don't scroll to
the target element — the client-side router updates the URL hash but
skips native scroll-to-anchor behavior.
- Changed 6 links across 5 docs pages to use fragment-only anchors (e.g.
`#task-inputs`), which bypass the router and let the browser handle
scrolling natively.