text: Title: docs: inline docs/includes to pages itself
  Body: We have a lot of `includes/` - https://github.com/airtai/faststream/tree/main/docs/includes files created to share them between different translations. But now, we don't plan to support multilanguage documentation anymore. So, we should inline such files to usages place to make documentation sources much easy to understand, support and work with.
  
  This is a huge work, so you can take care of any number of files you want – all PRs are welcome!
  
  PLEASE, DO NOT INLINE FILES ALREADY USING MULTIPLE TIMES