Sending Message to Student When Assignment is Graded

We would like the option to send an email to a student from the assignment grading page when the teacher assigns the grade to a submitted assignment. This seems to be a feature that used to be implemented, but it has disappeared.

What happens now:
1. Teacher creates an assignment.
2. Student makes a submission (and gets an email successfully).
3. Teacher marks an assignment. There is no option to indicate whether or not mark and comments should be sent to the student.
4. Student does not receive an email with mark and comments.

What we would like to happen:
At step 3 we would like the teacher to have a choice (maybe a checkbox).
At step 4, if the teacher has indicated that the student should get an email with the grade and feedback, then they will receive an email once the teacher has saved the grade for the assignment in Moodle.