Update bit_manipulation/count_of_set_bits.cpp

Co-authored-by: David Leal <halfpacho@gmail.com>

bit_manipulation/count_of_set_bits.cpp

@@ -64,6 +64,6 @@ static void test() {
  * @returns 0 on exit
  */
 int main() {
-    test();  // execute the test
+    test();  // run self-test implementations
     return 0;
 }