Fix small typo in Controller example (#295)

jbowes · balshetzer · commit 140ae90f29ea · 2019-05-17T10:58:38.000-04:00
diff --git a/gomock/controller.go b/gomock/controller.go
@@ -84,7 +84,7 @@ type TestHelper interface {
 // defer.
 //
 //   func TestFoo(t *testing.T) {
-//     ctrl := gomock.NewController(st)
+//     ctrl := gomock.NewController(t)
 //     defer ctrl.Finish()
 //     // ..
 //   }
