Standardize dishrack -> dish_rack

Posted under Tags

The bulk update request #13658 has been approved by @Hillside_Moose.

create alias dishrack -> dish_rack

"dish rack" is the more common name for the concept and this allows it to be found with a *_rack search.
Google for "dish rack": 3,040,000
Google for "dishrack": 739,000

I know this is a small tag that I could easily move over myself, but I'd like to make sure that I'm not missing anything and "dishrack" is also a valid spelling so this should help with findability.