docs: add documentation for ai-search locations and datasources configuration

[devin-ai-integration]

docs: add documentation for ai-search locations and datasources configuration

Summary

Adds comprehensive documentation for the new location and datasources configuration options in the ai-search section of docs.yml, which were introduced in PR #9788.

Changes:

• Created new documentation page: fern/products/ask-fern/pages/configuration/locations-and-datasources.mdx
• Added page to navigation in fern/products/ask-fern/ask-fern.yml under the Configuration section

The documentation covers:

• location field: configuring where Ask Fern appears (docs, slack, discord)
• datasources field: adding external content sources (website URLs)
• Complete usage examples
• Preview environment behavior
• Best practices

Review & Testing Checklist for Human

This is a yellow risk PR (documentation only, but based on schema inspection rather than actual feature testing).

• Verify feature accuracy: Test that the location and datasources fields actually work as documented. I documented based on the schema changes in PR #9788, but haven't tested the actual implementation.
• Check documentation rendering: Verify all custom MDX components (<ParamField>, <Note>, <AccordionGroup>, <Accordion>) render correctly on the docs site.
• Test examples: Try the complete example configuration in a test docs.yml to ensure it's valid and works as described.
• Verify preview behavior claims: I stated that preview environments use separate namespaces and that location config affects preview availability - please verify this is accurate.
• Test internal links: Verify the link to /ask-fern/features/slack-app works correctly.

Test Plan

1. Deploy the documentation changes to a preview environment
2. Verify all sections render correctly with proper formatting
3. Test a sample docs.yml configuration with both location and datasources fields
4. Confirm that the documented behavior matches actual feature behavior

Notes

• This documentation was created based on schema inspection from PR #9788 rather than hands-on testing of the feature
• The placement in the navigation (under Configuration, after Custom prompts) mirrors the logical grouping of configuration options
• Session: https://app.devin.ai/sessions/5c54bd0e425f46a282a2e17b5ef41979
• Requested by: sahil@buildwithfern.com (@sahil485)

[devin-ai-integration]

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[github-actions]

🌿 Preview your docs: https://fern-preview-961bdefa-b8fe-468b-a9b9-1c218c1dcd95.docs.buildwithfern.com/learn

[github-actions]

🌿 Preview your docs: https://fern-preview-7100f9ac-0695-4912-8da0-9b9010668bdc.docs.buildwithfern.com/learn

[github-actions]

🌿 Preview your docs: https://fern-preview-cce617e9-41a4-49fe-a1db-6e66340a73f2.docs.buildwithfern.com/learn