Allowing trailing whitespace

		$distributors = DB::table('distributors')
			->select(
				'distributors.id',
				'distributors.company_name',
				DB::raw('
					CONCAT_WS(\', \',
						IF(LENGTH(`address_1`), `address_1`, NULL),
						IF(LENGTH(`address_2`), `address_2`, NULL),
						IF(LENGTH(`city`), `city`, NULL),
						IF(LENGTH(`state`), `state`, NULL),
						IF(LENGTH(`zip`), `zip`, NULL)
					) AS address
				'),
				DB::raw('
					(
						SELECT COUNT(*)
						FROM redemptions
						WHERE redemptions.distributor_id = distributors.id
					) AS redemption_count
				')
			);

I like to format my DB::raws with space at the end.  It would be great if the clean_columns regex accommodated this as per my commit.  Thanks.