Addressed review comment

Author: H-G-Hristov

libcxx/include/__functional/reference_wrapper.h

@@ -62,7 +62,7 @@ class reference_wrapper : public __weak_result_type<_Tp> {
 
   // invoke
   template <class... _ArgTypes>
-  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __invoke_result_t<type&, _ArgTypes...>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __invoke_result_t<type&, _ArgTypes...>
   operator()(_ArgTypes&&... __args) const
 #if _LIBCPP_STD_VER >= 17
       // Since is_nothrow_invocable requires C++17 LWG3764 is not backported

libcxx/test/libcxx/diagnostics/functional.nodiscard.verify.cpp

@@ -56,9 +56,6 @@ void test() {
 
   std::reference_wrapper<int> rw{i};
   rw.get(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::function<int(int)> vf;
-  auto rwf = std::ref(vf);
-  rwf(1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
 
   std::ref(i);  // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
   std::cref(i); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}