docs: clarify LicenseChoice class name and purpose

- Add JavaDoc explaining 'Choice' refers to format selection
- Clarify it's not a license selection mechanism
- Add examples for better understanding
- Note mutual exclusivity of the two formats

Fixes #307

Signed-off-by: Sabah <sabashaikh361@gmail.com>

Signed-off-by: Sabah shaikh <sabahshaikh361@gmail.com>

Author: sabashaikh4