[libcxx-commits] [libcxx] [libc++][NFC] Update <any> to a more modern code style (PR #174619)

[Alexander Kornienko via libcxx-commits]

alexfh wrote:

> #include <any>
> #include <utility>
> #include "absl/status/statusor.h"
> 
> class Foo {
>  public:
>   Foo() = default;
> 
>   static Foo Repack(absl::StatusOr<Foo> v) {
>     return std::move(v).value();
>   }
> 
>  private:
>   explicit Foo(std::any value) : value_(std::move(value)) {};
> 
>   std::any value_;
> };

This boils down to the following (https://gcc.godbolt.org/z/oTfWdGvnd):
```
#include <any>

struct Foo {
  Foo(std::any v);
};

template <typename T, bool = std::is_copy_constructible<T>::value>
void f(T) {}

void q(Foo x) { f(x); }
```

https://github.com/llvm/llvm-project/pull/174619