Resolve "Ordering of affected lessons in register absence dialog is wrong"

Closes #342

added part::frontend source::customer::kath type::bug labels

assigned to @yuha

changed milestone to /AlekSIS%"[NLnet #6 (closed)] Fix bugs/missing small features from pilot schools"

this will need AlekSIS-Core!1659

added 3 commits

• 762e0c3e - Add indent to list items
• e7bbc671 - Return combined list of docs and dummies
• 4ead20a1 - Pass order_by argument

Compare with previous version

marked this merge request as ready

assigned to @hansegucker and unassigned @yuha