bed_sheet_background implication

Posted under Tags

The bulk update request #249 has been approved by @Lyren.

create implication bed_sheet_background -> bed_sheet

There cannot be a bed sheet background without a bed sheet.

This tag didn't exist before, but due to bed_sheet with its original wiki having over 90% mistags, I moved its wiki to this brand new tag. It's always been a confusing tag by its name and it's better to just keep both than try to remove all the mistags from it.