deprecate imminent_death

BUR #19845 has been rejected.

deprecate imminent_death

This tag came up in forum #253783. It seems to have been disambiguated already into dying and peril but no deprecation was made. Is there a fringe case it’s preferable over the others?

This bulk update request is pending automatic rejection in 5 days.

This bulk update request has been rejected because it was not approved within 45 days.

The bulk update request #19845 (forum #253787) has been rejected by @DanbooruBot.