(super)hero(es) keywords issue

According to the keywords guide (https://help.imdb.com/article/contribution/titles/keywords/GXQ22G5Y72TH8MJ5?ref_=helpms_helpart_inli...#) keywords should be singular, not plural. Therefore I'd like to ask a staffer to merge the keyword heroes (currently attached to 68 titles, https://www.imdb.com/search/keyword/?keywords=heroes) into the keyword hero (https://www.imdb.com/search/keyword/?keywords=hero). Can you also merge superheroes (listed for 36 titles, https://www.imdb.com/search/keyword/?keywords=superheroes) and super-heroes (14 titles, https://www.imdb.com/search/keyword/?keywords=super-heroes) into superhero (https://www.imdb.com/search/keyword/?keywords=superhero)?

Perhaps you can contact the contributors that added these keywords or add a warning or a block or something to prevent this from happening in the future...