improv(coro): add [[nodiscard]] to dpp::task, dpp::coroutine

include/dpp/coro/coroutine.h

@@ -70,7 +70,7 @@ using handle_t = std_coroutine::coroutine_handle<promise_t<R>>;
  * @tparam R Return type of the coroutine. Can be void, or a complete object that supports move construction and move assignment.
  */
 template <typename R>
-class coroutine : public basic_awaitable<coroutine<R>> {
+class [[nodiscard("dpp::coroutine only starts when it is awaited, it will do nothing if discarded")]] coroutine : public basic_awaitable<coroutine<R>> {
 	/**
 	 * @brief Promise has friend access for the constructor
 	 */

include/dpp/coro/task.h

@@ -92,7 +92,7 @@ template <typename R>
 #ifndef _DOXYGEN_
 requires (!std::is_reference_v<R>)
 #endif
-class task : public awaitable<R> {
+class [[nodiscard("dpp::task cancels itself on destruction. use co_await on it, or its sync_wait method")]] task : public awaitable<R> {
 	friend struct detail::task::promise_t<R>;
 
 	using handle_t = detail::task::handle_t<R>;