Googletest export

Update example Environment class destructor annotation

PiperOrigin-RevId: 283986183

googletest/docs/advanced.md

@@ -1231,7 +1231,7 @@ environment, which knows how to set-up and tear-down:
 ```c++
 class Environment : public ::testing::Environment {
  public:
-  virtual ~Environment() {}
+  ~Environment() override {}
 
   // Override this to define how to set up the environment.
   void SetUp() override {}