P3168R2 `std::optional` Range Support

WG21-P3168R2 `std::optional` Range Support
WG21-P3913R1 Optimize For `std::optional` In Range Adaptors

Feature-test macro:
```cpp
#define __cpp_lib_optional_range_support 202406L
```

Note: We're focused on implementing the remaining library-only [features in C++23](https://github.com/orgs/microsoft/projects/1142/views/2). Until that's done, we will **NOT** be accepting PRs for C++26 features.