fastly::log::Endpoint doesn't implement the <iostream> interfaces.

[harmony7]

I've noticed that while the code comment for fastly::log::Endpoint says I should write to the endpoint using the <iostream> interfaces, the code for the class doesn't actually implement std::ostream.

So currently it seems there is no way to output to an Endpoint instantiated using fastly::log::Endpoint::from_name().

Note this class doesn't inherit from anything:

compute-sdk-cpp/include/fastly/log.h

Lines 417 to 425 in 57984bc

	/// A Fastly logging endpoint.
	///
	/// To write to this endpoint, use the `<iostream>` interface:
	///
	/// ```cpp
	/// auto endpoint{fastly::log::Endpoint::from_name("my_log_endpoint")};
	/// endpoint << "stuff happened y'all";
	/// ```
	class Endpoint {

Additionally, the code comment above shows fastly::log::Endpoint::from_name() being used as though it returns an fastly::log::Endpoint instance directly, but the actual SDK returns expected<fastly::log::Endpoint>.

compute-sdk-cpp/src/cpp/log.cpp

Line 19 in 57984bc

fastly::expected<Endpoint> Endpoint::from_name(std::string_view name) {