C++: add test for getReferencedMember

Author: IdrissRio

cpp/ql/test/library-tests/comments/binding/commentBinding.expected

@@ -9,3 +9,5 @@
 | multi.c:5:27:5:36 | // Multi 3 | declaration of multi3 |
 | templates.cpp:3:3:3:8 | // Foo | declaration of foo |
 | templates.cpp:7:3:7:8 | // Bar | definition of bar |
+| templates.cpp:16:3:16:20 | // using T::member | using member |
+| templates.cpp:19:3:19:28 | // using T::nested::member | using member |

cpp/ql/test/library-tests/comments/binding/templates.cpp

@@ -10,3 +10,12 @@ class Cl {
   }
 };
 
+
+template <typename T>
+class Derived : public T {
+  // using T::member
+  using T::member;
+
+  // using T::nested::member
+  using T::nested::member;
+};