P2165R4: Compatibility between `tuple`, `pair` and `tuple-like` objects

[ldionne]

Link: https://wg21.link/P2165R4

BEGIN-RST-NOTES
Only the part for ``zip_view`` is implemented.
END-RST-NOTES

[frederick-vs-ja]

Oh, the note I wrote was wrong. There're actually other parts implemented.

• Helper concepts. Done in 9446182 (https://reviews.llvm.org/D136268).
• Update basic_common_reference<tuple, tuple-like> and common_type<tuple, tuple-like>.
• Constrain tuple_cat, apply, and make_from_tuple.
• Add new tuple constructors, operator=, operator==, and operator<=>.
• Add new pair constructors and operator=. Done in 9e35fc0 (https://reviews.llvm.org/D143914).
• Update type detection in deduction guides for containers. Done in [libc++] P2165R4: Update deduction guides for map containers and container adaptors #136011.
• Update constraints for subrange conversion. Done in 9446182 (https://reviews.llvm.org/D136268). Applied to C++20 mode.
• Update constraints for views::elements. Done in 9446182 (https://reviews.llvm.org/D136268). Applied to C++20 mode.
• Update zip_view and its iterator. Done in [libc++][ranges] LWG3692: zip_view::iterator's operator<=> is overconstrained and changes of zip_view in P2165R4 #112077.
• Update adjacent_view and its iterator. Not done because adjacent_view isn't implemented; likely to be done in the PR implementing adjacent_view.
• Update cartesian_product_view and its iterator. Not done because cartesian_product_view isn't implemented; likely to be done in the PR implementing cartesian_product_view.