Fix documentation perm check for amended lessons

aleksis/apps/alsijil/util/predicates.py

@@ -193,6 +193,7 @@ def is_lesson_event_group_owner(user: User, obj: LessonEvent):
     Checks whether the person linked to the user is a owner of any group
     (or their respective parent groups) linked to the lesson event,
     or a owner of any group linked to the course, if the lesson event has one.
+    Also checks for groups linked to the lesson being amended, if one exists.
     """
     if obj:
         for g in obj.groups.all():
@@ -201,6 +202,13 @@ def is_lesson_event_group_owner(user: User, obj: LessonEvent):
             for pg in g.parent_groups.all():
                 if user.person in pg.owners.all():
                     return True
+        if obj.amends:
+            for g in obj.amends.groups.all():
+                if user.person in g.owners.all():
+                    return True
+                for pg in g.parent_groups.all():
+                    if user.person in pg.owners.all():
+                        return True
     return False