Feat: nicer display of missing (sub)exercises

[gasche]

Related project scope(s) (ex: client, CSS, grading, etc...) : web frontend, CSS, grading

The problem

If you have several questions inside a single exercise, the display does not feel very nice for students that have only answered a subset of the questions so far: missing questions are displayed in red as "wrong".

Wanted solution

It would be nice if the grader could detect that the question is not "wrong" but "missing", and display it in a more neutral style (gray ?) in the report.

Considered alternatives

It is possible to use different exercises for each question, but not so pleasant. This is what @smdsousa does to avoid the issue.

[erikmd]

Thanks @gasche for the suggestion!

I agree that this is something that could be improved (and shouldn't be too difficult to implement at first sight (but I don't assign myself this issue for the moment - lacking of time this week 😅))

− Regarding the alternative you mention, currently it is the standard workaround to limit the size of a grader, indeed; but note that in the medium term, the nice feature started by @YoanwM (#402) could be a native way to "split a long grader"…