To add on, students won't really learn from this. They'll check their grade and throw it in the bag. My advice is to never nitpick and to avoid covering a paper in ink! It screws up students' self-efficacy and a number of other things.

To really save time and provide maximum benefit, pick out two to three systematic errors per writing assignment (not mistakes -- mistakes are accidental). Point them out with direct feedback. You might also simply highlight the errors and let the student try to figure out the problem (learning is longer lasting and more effective with exerted effort).

This comment would be for teenage and up with at least B1 proficiency.