Argument-dependent lookup will not find to_string() overloads in the global namespace if the argument and the caller are in other namespaces. Move these to_string() overloads to std:: so ADL will find them. Found by clang.
Argument-dependent lookup will not find to_string() overloads in the global namespace if the argument and the caller are in other namespaces. Move these to_string() overloads to std:: so ADL will find them. Found by clang.