[typeinfo] std/fmt formatter

[GuillaumeDua]

See demo: https://godbolt.org/z/nTjq9sT5h

fmt::println("{:-^9}", typenamed(42));
fmt::println("{:-^9}", typenamed(42, " = "));
fmt::println("{:-^9}", 42 | views::typenamed);
fmt::println("{}", typenamed(std::vector{1,2,3}));
fmt::println("{}", std::vector{1,2,3} | views::typenamed);

expected output:

int: ---42----
int = ---42----
int: ---42----
std::vector<int>: [1, 2, 3]
std::vector<int>: [1, 2, 3]