No Self.DoubleWidth and Self.Plus1 aliases

[oscbyspro]

From oscbyspro/Numberick#12

The NBKDoubleWidth model has a type alias called DoubledWidth, which is double the width of Self. It makes sense, but I would prefer not having things break if I decide to remove the NBK prefix. I considered renaming it Doubled but decided against it. I'm also not convinced it reads better than NBKDoubleWidth<Self> because there's value in consistency. I don't want an alias that appears once or twice to be a source of confusion.

Note: It was less of a problem with a model name like ANKFullWidth, but the last point still stands.