docs(other): fix broken links and redirects

[JLekawa]

What/Why/How?

Fixes links broken by deleting navigation.md

Reference

Closes https://github.com/Redocly/redocly/issues/23232

Testing

Screenshots (optional)

Check yourself

• Code is linted
• Tested
• All new/updated code is covered with tests

Security

• Security impact of change has been considered
• Code follows company security practices and guidelines

[redocly]

marketing-site AI Review: 🟢 Completed

Reunite Bot has reviewed your changes and found 3 potential issue(s).

Note

Low Risk

This PR contains minor documentation and configuration updates to fix broken links and redirects. It does not introduce changes to the application code, so there is practically no risk of regression.

Overview

Updates broken navigation links caused by the deletion of navigation.md. Specifically, it replaces references to /docs/realm/navigation/navigation with /docs/realm/navigation in two migration guides (migrate-from-legacy-portal.md and migrate-api-reference.md) and updates two outdated redirect destinations in redirects.yaml.

[redocly]

The redirect points to the consolidated '/docs/realm/navigation/' path, but 'navigation.md' still exists and is referenced in 'sidebars.yaml', 'config/breadcrumbs.md', and 'config/sidebar.md'. Ensure the file is deleted and all references are fully updated.

[redocly]

Since navigation.md is consolidated, consider adding a redirect from '/docs/realm/navigation/navigation' to '/docs/realm/navigation/'. This prevents 404 errors for users with bookmarks or external links pointing to the old page.

[redocly]

The redirect for '/docs/realm/author/how-to/configure-nav/navigation-buttons' should point to '/docs/realm/config/navigation' (where navigation buttons are actually configured) instead of the general '/docs/realm/navigation' page, to maintain the correct context.