bellbottoms -> bell-bottoms

BUR #7509 has been approved by @nonamethanks.

create alias bellbottoms -> bell-bottoms
create alias flare_pants -> bell-bottoms
create alias flares_(pants) -> bell-bottoms

I found some of these under flares and of course we're also using the wrong spelling for it.

I cleaned up flares and moved the airplane things into flares (countermeasure).

The bulk update request #7509 (forum #198171) has been approved by @nonamethanks.