Gull-wing door

BUR #51431 has been approved by @nonamethanks.

create alias gullwing_doors -> gull-wing_doors

Wikipedia has the hyphen, not sure why the tag doesn't.

The bulk update request #51431 (forum #401477) has been approved by @nonamethanks.

Doing this for consistency, but wikipedia itself doesn't seem to be very consistent even in that article. I wouldn't be surprised if there isn't a real consensus anywhere on the hyphen.