Update example.cpp

Author: Jesse

example.cpp

@@ -38,14 +38,10 @@ int main(int argc, const char* argv[]) {
     switch (parser.get<unsigned int>("v")) {
       case 2:
         std::cout << "an even more verbose string" << std::endl;
-#ifdef __GNUC__
-        [[gnu::fallthrough]];
-#endif
+        // fall through
       case 1:
         std::cout << "a verbose string" << std::endl;
-#ifdef __GNUC__
-        [[gnu::fallthrough]];
-#endif
+        // fall through
       default:
         std::cout << "some verbosity" << std::endl;
     }