Group week view: Highlight missing register entries

• Annotate the lesson_periods query in the group_week view with a field that is True exactly if there is a LessonDocumentation linked to the period and that linked documentation has a non-empty topic (@mirabilos)
• Use that field in the template to highlight lesson periods without documentation (@nik)

changed milestone to %1.0a1

added part::frontend prio::1 source::customer type::feature labels

assigned to @mirabilos

changed title from Lint view: Show missing register entries and other problems to Lint view: Show missing register entries

changed the description

changed title from Lint view: Show missing register entries to Group week view: Highlight missing register entries

changed milestone to %1.0a0

mentioned in commit 821a2e12

marked the checklist item Annotate the lesson_periods query in the group_week view with a field that is True exactly if there is a LessonDocumentation linked to the period and that linked documentation has a non-empty topic (@mirabilos) as completed

assigned to @nik and unassigned @mirabilos

mentioned in commit a5665154

closed via commit 8b889eba