Update graph/topological_sort.cpp

Co-authored-by: realstealthninja <[email protected]>

Author: HarshilShah1804

graph/topological_sort.cpp

@@ -178,6 +178,6 @@ static void test() {
  * @returns 0 on exit
  */
 int main() {
-    test();
+    test(); // run self test implementations
     return 0;
 }