docs: fix reference links

[charles-openclaw]

No description provided.

[charles-openclaw]

Summary

• Fix the Python API docs model_config link so it points at the existing model reference page.
• Fix malformed Markdown around the datasets.load_dataset documentation link in the offline evaluation page.

Verification

• Ran a focused Markdown relative-link check for docs/source/using-the-python-api.mdx and docs/source/offline-evaluation.md (missing_relative_links=0).
• Ran a focused assertion confirming the stale package_reference/model_config target and malformed ]((https://...)) link syntax are gone.
• Ran git diff --check.