docs: Custom REST handlers documentation

[kkedziak-splunk]

Issue number:

PR Type

What kind of change does this PR introduce?

• Feature
• Bug Fix
• Refactoring (no functional or API changes)
• Documentation Update
• Maintenance (dependency updates, CI, etc.)

Summary

Changes

Documentation changes for:

• feat: add support for custom REST handlers without UI in openapi.json #1529
• feat: add support for custom REST handlers without UI in web.conf and restmap.conf #1532

User experience

No changes.

Checklist

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• I have performed a self-review of this change according to the development guidelines
• Tests have been added/modified to cover the changes (testing doc)
• Changes are documented
• PR title and description follows the contributing principles

[kkedziak-splunk]

Suggested pull request title: docs: add documentation for custom REST handlers configuration

I appreciate the well-structured and comprehensive documentation you've added for the REST handlers configuration options. The documentation is clear, includes good examples, and follows proper markdown formatting standards.

However, there are a few minor improvements that could make the documentation even better:

1. In docs/options/rest_handlers.md:

   • Consider adding a brief introduction paragraph explaining what REST handlers are and when users might need custom ones
   • The table formatting could be improved by removing extra vertical bars to be consistent with other documentation
   • Consider adding a note about security implications of custom REST handlers
   • It might be helpful to add a complete example of a handler implementation file

2. In docs/options/index.md:

   • Consider expanding the introduction to explain what the options section is used for in more detail
   • Add a note about where in the configuration hierarchy these options should be placed

3. In mkdocs.yml:

   • The indentation of the new Options section could be aligned with other sections for better consistency

Despite these suggestions, the documentation is already quite thorough and ready to be merged. The examples are particularly helpful, and the parameter descriptions are clear and complete.

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