[ESnext] Implement Object Rest

src/messages.h

Index: src/messages.h
diff --git a/src/messages.h b/src/messages.h
index 8e38ff0de8d5d23bc36d3d02d077cc91a7128bd0..3da34d4bb4b200ffc854b5dfcadbdf015fe6d9c1 100644
--- a/src/messages.h
+++ b/src/messages.h
@@ -588,7 +588,7 @@ class ErrorUtils : public AllStatic {
   T(PushPastSafeLength,                                                        \
     "Pushing % elements on an array-like of length % "                         \
     "is disallowed, as the total surpasses 2**53-1")                           \
-  T(ElementAfterRest, "Rest element must be last element in array")            \
+  T(ElementAfterRest, "Rest element must be last element")                     \
   T(BadSetterRestParameter,                                                    \
     "Setter function argument must not be a rest parameter")                   \
   T(ParamDupe, "Duplicate parameter name not allowed in this context")         \