Fixes#135351
This PR update CATD guides to associative containers (`std::map`,
`std::multimap`, `std::unordered_map`, `std::unordered_multimap`,
`std::flat_map`, `std::flat_multimap`).
- Updated template alias for deduction guides for the relevant
associative containers.
- Added a new test to verify the deduction guides with `std::map`,
`std::multimap`, `std::unordered_map`, `std::unordered_multimap`,
`std::flat_map`, `std::flat_multimap`.
b71255705b