integration: Sync Superlinked Retriever integration docs fixes #538

[fm1320]

• Add provider documentation (superlinked.mdx)
• Add retriever documentation (superlinked.mdx)
• Add retriever examples (superlinked_examples.mdx)
• Update navigation in retrievers index and providers list
• Convert all files from Docusaurus/Jupyter format to Mintlify MDX

Fixes #538

Overview

Type of change

Type: [Replace with: New documentation page / Update existing documentation / Fix typo/bug/link/formatting / Remove outdated content / Other]

Related issues/PRs

• GitHub issue:
• Feature PR:

• Linear issue:
• Slack thread:

Checklist

• I have read the contributing guidelines
• I have tested my changes locally using docs dev
• All code examples have been tested and work correctly
• I have used root relative paths for internal links
• I have updated navigation in src/docs.json if needed
• I have gotten approval from the relevant reviewers
• (Internal team members only / optional) I have created a preview deployment using the Create Preview Branch workflow

Additional notes

[fm1320]

@mdrxy making progress on this will be ready very soon

[mdrxy]

A few things;

• Providers index should not be manually edited. Please add an entry to packages.yml and run uv run python pipeline/tools/partner_pkg_table.py from root
• Please consolidate all examples to the providers page. No dedicated examples pages. Feel free to make use of Mintlify accordions (see other docs for examples)
• The python.langchain refs url link you included doesn't exist, and that is now our old docs.

Let's touch back after 1 & 2 are done and then I can help get you into the new consolidated refs https://reference.langchain.com/python/integrations/