Fix code suggestion in test

Author: sanxiyn

src/test/compile-fail/issue-2392.rs

@@ -81,11 +81,11 @@ impl FuncContainerOuter {
     fn run(&self) {
         unsafe {
             (*self.container).f1(1); //~ ERROR no method named `f1` found
-            //~^ NOTE use `(*self.container.f1)(...)`
+            //~^ NOTE use `((*self.container).f1)(...)`
             (*self.container).f2(1); //~ ERROR no method named `f2` found
-            //~^ NOTE use `(*self.container.f2)(...)`
+            //~^ NOTE use `((*self.container).f2)(...)`
             (*self.container).f3(1); //~ ERROR no method named `f3` found
-            //~^ NOTE use `(*self.container.f3)(...)`
+            //~^ NOTE use `((*self.container).f3)(...)`
         }
     }
 }