Fixes aitjcize#143

…e#189)

* Update README.rst

- Implement hybrid search strategy that tries std:: prefix first
  - Searches for std::<pattern> before falling back to original pattern
  - Returns std:: results early if >= 5 matches found
  - Combines both result sets if std:: results are sparse

- Change default behavior to show first match directly
  - Reverts selection menu from default cppman <page> behavior
  - Provides faster access to most common use case

- Move interactive selection menu to -f flag
  - cppman -f <keyword> now shows paginated selection menu
  - Menu displays 20 results per page
  - Navigation: 'n'/'next' for next page, 'p'/'prev' for previous
  - Enter number to select, Enter alone to cancel

- Update documentation
  - Updated program help text to explain new behavior
  - Updated man page with smart search and pagination details
  - Added -n/--max-results option documentation

This improves UX by reducing noise (e.g., 'cppman map' shows std::map
directly) while still providing comprehensive search via -f flag.