feature: Opt out pages

[aristideubertas]

Is your feature request related to a problem? Please describe.

Instead of specifying which MD pages to include, specify an opt out.

Describe the solution you'd like

MD pages added to the llms-txt automatically even when inside a nested structure.

Describe alternatives you've considered

Including all pages, but requires manual update when new features added

Additional context

Raised by @Kludex at pydantic/pydantic-ai#1427 (comment)

[pawamoy]

Thanks for the feature request @aristideubertas 🙂

I could see a flag to reuse pages defined in the nav, only keeping the top-level sections as section separator.

Would that cater to your use-case, or do you really need to include all then exclude specific pages?