Added the list of valid pairs

[ksandeep18]

Update Valid Pairs List in Kernel_23 Documentation

Description

This pull request updates the documentation in the Kernel_23 module to include a comprehensive list of valid pairs. The changes aim to improve clarity and provide more detailed information for developers working with the CGAL library.

Updated file path: cgal/Kernel_23/doc/Kernel_23/Kernel_23.txt`

Changes

• Added a new section in the Kernel_23 documentation listing valid pairs.
• Updated existing content to reference the new list.
• Improved formatting for better readability.

Questions

• Are there any additional pairs that should be included in the list?
• Is the current formatting optimal for readability?

Summary of Changes

Updated the documentation to explicitly state that Point_2 and Circle_2, and Point_3 and Sphere_3 are valid combinations of parameters for the CGAL::intersection() function.

Release Management

• Affected package(s): Kernel_23
• Issue : fix The reference-manual page of intersection() is missing some valid combinations of parameters #8756