Example in Object.MemberwiseClone method is obsolete

The method [```string.Copy()```](https://docs.microsoft.com/pt-br/dotnet/api/system.string.copy) in the [Object.MemberwiseClone](https://docs.microsoft.com/en-us/dotnet/api/system.object.memberwiseclone) example's obsolete because it's not used to create mutable strings.

```csharp
public Person DeepCopy()
{
Person other = (Person) this.MemberwiseClone();
other.IdInfo = new IdInfo(IdInfo.IdNumber);
other.Name = String.Copy(Name);
return other;
}
```