feat: Serialize multiple categories and resources to one line

[NRG-Drink]

It's allowed to have CATEGORIES property multiple times in an event but it's not that pretty and some other programs will have trouble reading such events. So it's more a feature than a bug (#156).
Here is a quick fix to display multiple categories in one line.

[axunonb]

Thanks, very good! See comments if your time allows.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[axunonb]

That was fast, great! Thanks for your support.
Would you like to join the ical.net party?

[NRG-Drink]

That was fast, great! Thanks for your support. Would you like to join the ical.net party?

You were even faster. I wasn't done and there is an error in the test 😅
btw. is it possible that ATTENDEE is broken? I tried to enable oneline for attendees too but it only performs a ToString on it and not serializing it properly. I think I will leave it for the moment.

[NRG-Drink]

That was fast, great! Thanks for your support. Would you like to join the ical.net party?

I can try to help out on smaller tasks if it helps 😊

[axunonb]

btw. is it possible that ATTENDEE is broken? I tried to enable oneline for attendees

Attendee requires its own AttendeeSerializer, as it's more complex than e.g. CATEGORIES. That's why.

You were even faster.

Should have awaited your review request, right