fix: Add history line when changing the review deadline. (fixes ietf-tools#6598) (ietf-tools#7194)

* Add history line when changing the review deadline.

* chore: reduce redundancy

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Co-authored-by: Robert Sparks <rjsparks@nostrum.com>

Author: kivinen

ietf/doc/views_review.py

@@ -1053,7 +1053,11 @@ def edit_deadline(request, name, request_id):
         if form.is_valid():
             if form.cleaned_data['deadline'] != old_deadline:
                 form.save()
-                subject = "Deadline changed: {} {} review of {}-{}".format(review_req.team.acronym.capitalize(),review_req.type.name.lower(), review_req.doc.name, review_req.requested_rev)
+                subject = f"Deadline changed: {review_req.team.acronym.capitalize()} {review_req.type.name.lower()} review of {review_req.doc.name}"
+                if review_req.requested_rev:
+                    subject += f"-{review_req.requested_rev}"
+                descr = "Deadine changed from {} to {}".format(old_deadline, review_req.deadline)
+                update_change_reason(review_req, descr)
                 msg = render_to_string("review/deadline_changed.txt", {
                     "review_req": review_req,
                     "old_deadline": old_deadline,