Revert "Don't make positional __args__ required if present"
Revert "Don't make positional __args__ required if present"

This reverts commit b78bfea72f3ae2c049192feba554b0c9da14fdd0.

explosion/thinc,explosion/thinc,explosion/thinc,spacy-io/thinc,spacy-io/thinc,explosion/thinc,spacy-io/thinc