Add lang items for AsyncFn's associated types

compiler/rustc_span/src/symbol.rs

@@ -441,6 +441,7 @@ symbols! {
         async_fn_kind_helper,
         async_fn_mut,
         async_fn_once,
+        async_fn_once_output,
         async_fn_track_caller,
         async_fn_traits,
         async_for_loop,
@@ -498,6 +499,8 @@ symbols! {
         call,
         call_mut,
         call_once,
+        call_once_future,
+        call_ref_future,
         caller_location,
         capture_disjoint_fields,
         catch_unwind,