Danish holiday calendar has events that have descriptions instead of names

[nclm]

Originally opened at https://bugzilla.mozilla.org/show_bug.cgi?id=1896754 but looking into it, it seems that here is the place? I could do a PR changing the files, but it seems that the calendar are generated, though I’m not sure how.

It’s about the Danish holiday calendar at https://www.thunderbird.net/media/caldata/autogen/DenmarkHolidays.ics

Instead of names of the holidays in SUMMARY, four events have entire sentences instead, which appear in calendar apps as names. The events should be instead: “Langfredag”, “Kristi himmelfartsdag”, “Pinsedag”, and “Anden pinsedag” (may be double checked with a native Dane).