text: Title: Demo for highlighting text in a pdf file for LLM RAG purposes
  Body: - [x] I have searched to see if a similar issue already exists.
  
  **Is your feature request related to a problem? Please describe.**  
  I wanted a way to simply show a PDF with highlighted text at the right page (for LLM RAG purposes).
  
  **Describe the solution you'd like**  
  A demo to build such an app.
  