add message when cli train script throws exception (#5009)
add message when cli train script throws exception (#5009)

* add message when cli train script throws exception

* fix formatting

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