Feature request: do not overwrite existing fields on recollection

[sdrobert]

Hello,

This term, a number of students asking for remarks had made small errors that our TAs had to manually fix. In order to run tests on the updated files, we had to recollect the submissions. This deleted the content of all existing fields, not just the ones that were auto-tested. This includes the remark request itself and any feedback the TA had previously given.

While there may be a good use case for clearing all fields on recollection, I think there should definitely be an option for keeping the values of existing fields.

Thanks for your time,
Sean