@Override
    public DocumentType clone() {
        DocumentType type = (DocumentType) super.clone();
        type.contentStructType = contentStructType.clone();
        type.inherits = new ArrayList<>(inherits.size());
        type.inherits.addAll(inherits);
        return type;
    }
Creates a new document type and registers it with the document type manager.
Implicitly registers this with the document type manager.
The document type id will be generated as a hash from the document type name.

@param name       The name of the new document type
@param contentStructType The type of the content struct
document/src/main/java/com/yahoo/document/DocumentType.java