[APPROVED] Update hikawa_kyoka -> hikawa_kyouka

BUR #2258 has been approved by @evazion.

mass update hikawa_kyoka_(cosplay) -> hikawa_kyouka_(cosplay)
mass update hikawa_kyoka -> hikawa_kyouka

Reason: Following danbooru's romanization rules. From https://dic.pixiv.net/a/%E6%B0%B7%E5%B7%9D%E9%8F%A1%E8%8F%AF it's ひかわきょうか (Hikawa Kyouka).

EDIT: The bulk update request #2258 (forum #162533) has been approved by @evazion.

The bulk update request #2258 (forum #162533) has been approved by @evazion.