Could C++/WinRT consider adding a basic_cstring_view?

[YexuanXiao]

Summary

As I mentioned in the comment of issue 1529, std::basic_cstring_view won't be available until C++29. Raising C++/WinRT's minimum standard to C++29 seems quite distant for both v2 and the future v3, so why don't we implement it first? I believe it should at least remain a template, which would facilitate easier migration to the future std::basic_cstring_view. Then, it only needs to implement the functions required by C++/WinRT, such as constructors, comparison operators, etc., to reduce maintenance burden and avoid implementing functions that won't exist in std::basic_cstring_view as much as possible.

Note that the latest C++ proposal is P3655R3. The authors of the two previously parallel proposals have decided to merge them and agreed that the name should be basic_cstring_view, not basic_zstring_view.