Change `@JsonTypeInfo.defaultImpl` default value to deprecate `JsonTypeInfo.None.class`

[cowtowncoder]

As per javadocs (which suggest this was to happen in 2.6 already :) ), change default placeholder value, to deprecate unnecessary None.class (inner class).

[cowtowncoder]

Hmmh. Actually... looks like Void.class has implicit meaning of "deserialize as null, if type not found", so that can not be used. But will figure out some other placeholder, if possible (any annotation type would work).