chore: use iwyu on data_structures/**.cpp

data_structures/test_stack_students.cpp

@@ -8,14 +8,15 @@
  *     ./main student.txt
  ************************************************************
  * */
-#include <cassert>
-#include <cmath>
-#include <fstream>
-#include <iomanip>
-#include <iostream>
-#include <string>
+#include <cassert>      // for assert
+#include <cmath>        // for NAN
+#include <fstream>      // for basic_ostream, basic_ifstream, basic_istream
+#include <iomanip>      // for operator<<, setprecision, _Setprecision
+#include <iostream>     // for cout
+#include <string>       // for char_traits, operator>>, basic_string, operat...
+#include <memory>       // for operator==
 
-#include "./stack.hpp"
+#include "./stack.hpp"  // for stack
 
 int main(int argc, char* argv[]) {
     double GPA = NAN;