I only tried briefly but could only get strikethough to work in the description field. I didn't try them all separately though. I have found sometimes with these things you need to paste and copy into some application that only handles text. Might have to experiment.
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B̶o̶o̶!̶
Edit: Interesting. The Bold Script one doesn't seem to work here. Original comment had "Yay" in script after the strikethrough "Boo."
I only tried briefly but could only get strikethough to work in the description field. I didn't try them all separately though. I have found sometimes with these things you need to paste and copy into some application that only handles text. Might have to experiment.