Updated test cases documentation

docs/test_cases/t00013.md

@@ -55,6 +55,11 @@ template <typename T> struct E {
     T e;
 };
 
+template <typename T, typename... Args> struct G {
+    T g;
+    std::tuple<Args...> args;
+};
+
 using namespace ABCD;
 class R {
 public:
@@ -73,6 +78,8 @@ public:
     template <typename T> T get_f(const F<T> &f) { return f.f; }
     int get_int_f(const F<int> &f) { return f.f; }
 
+    G<int, float, std::string> gintstring;
+
 private:
     mutable E<std::string> estring;
 };