RS: unreadable calendars

It is possible to write in a calendar event a description with special characters and line breaks. Some combinations of them are not supported by the calendar parser and produce red screens. Sadly, they can be saved without problems and the calendar is useable until evicted from the cache. Example of such:

Weitere Bereiche der Kognition: Sprache, Denken, Problemlös
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If a description has line breaks but doesn't produce a red screen, the text after the line breaks is still lost.