Fix default argument in TextCategorizer.Model (resolves #3221)
Fix default argument in TextCategorizer.Model (resolves #3221)

explosion/spaCy,honnibal/spaCy,honnibal/spaCy,explosion/spaCy,spacy-io/spaCy,spacy-io/spaCy,explosion/spaCy,honnibal/spaCy,explosion/spaCy,spacy-io/spaCy,honnibal/spaCy,spacy-io/spaCy,explosion/spaCy,spacy-io/spaCy,explosion/spaCy,spacy-io/spaCy