Nearly identical to {@link switchOffsetCol()} except it forces teh class to be returned as its column
(e.g. "span") width counterpart. It is also safe to pass in a class that is already the column width and it will
re-return it. For example, passing in col-md-offset-2 will return col-md-2. Passing in col-md-4 will still
return col-md-4.