Alias holding_trident to holding_polearm

BUR #16494 has been rejected.

create alias holding_trident -> holding_polearm

Trident is a type of polearm.

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 #16494 (forum #239866) has been rejected by @DanbooruBot.