Fix Doc.to_array when only one string attr provided
Fix Doc.to_array when only one string attr provided

recognai/spaCy,spacy-io/spaCy,honnibal/spaCy,explosion/spaCy,explosion/spaCy,explosion/spaCy,spacy-io/spaCy,honnibal/spaCy,aikramer2/spaCy,explosion/spaCy,explosion/spaCy,spacy-io/spaCy,recognai/spaCy,explosion/spaCy,spacy-io/spaCy,aikramer2/spaCy,spacy-io/spaCy,recognai/spaCy,aikramer2/spaCy,recognai/spaCy,aikramer2/spaCy,spacy-io/spaCy,honnibal/spaCy,honnibal/spaCy,recognai/spaCy,recognai/spaCy,aikramer2/spaCy,aikramer2/spaCy