P3772R2 `simd` Overloads For Bit Permutations

WG21-P3772R2 `simd` Overloads For Bit Permutations

**INCREASED** feature-test macro, **NOTE** special interaction with #6340 WG21-P3793R2 Better Shifting which added this macro:

```cpp
#define __cpp_lib_simd_bitops 202607L
```

Note: We are not yet accepting PRs for C++29 features.
