formatted_size misses locale overload

[gerboengels]

formatted_size doesn't have an overload which takes a locale (overloads 3 and 4 on cpp reference).

Godbolt link (using MSVC to compare with its std implementation, which does support this overload): https://godbolt.org/z/94dsPhTMb

[vitaut]

It's just a matter of adding an overload similar to

fmt/include/fmt/core.h

Lines 3284 to 3291 in 1feb430

	template <typename... T>
	FMT_NODISCARD FMT_INLINE auto formatted_size(format_string<T...> fmt,
	T&&... args) -> size_t {
	auto buf = detail::counting_buffer<>();
	detail::vformat_to(buf, string_view(fmt),
	format_args(fmt::make_format_args(args...)), {});
	return buf.count();
	}

but taking and forwarding the locale. This overload should be added here:

fmt/include/fmt/format.h

Line 4272 in 1feb430

A PR is welcome.