add syntax test

Author: mununki

res_syntax/tests/parsing/grammar/expressions/await.res

@@ -23,4 +23,8 @@ let () = {
 let () = {
     await delay(10)
     await delay(20)
-}
+}
+
+let forEach = await Js.Import(Belt.List.forEach)
+
+module M = await Belt.List

res_syntax/tests/parsing/grammar/expressions/expected/await.res.txt

@@ -15,4 +15,6 @@ let () =
   [@res.braces ])
 let () = ((delay 10)[@res.braces ][@res.await ])
 let () = ((((delay 10)[@res.await ]); ((delay 20)[@res.await ]))
-  [@res.braces ])
+  [@res.braces ])
+let forEach = ((Js.Import Belt.List.forEach)[@res.await ])
+module M = ((Belt.List)[@res.await ])