add artist_request to images without an artist tag

BUR #259 has been rejected.

mass update arttags:0 -artist_request -> artist_request

add artist_request to images without an artist tag so that people can either know to tag an image with an artist if they know or to ask for one from the uploader.

I don't see a reason to tag images such as off-topic with artist_request.

Lyren said:

I don't see a reason to tag images such as off-topic with artist_request.

hmm, perhaps I update it to exclude those

BUR #260 has been rejected.

mass update arttags:0 -artist_request -off-topic -> artist_request

no reason to include off-topic in this

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 #259 (forum #1796) has been rejected by @DanbooruBot.

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

The bulk update request #260 (forum #1799) has been rejected by @DanbooruBot.