Update debug data for textcat (#8066)
Update debug data for textcat (#8066)

* Check for unsupported cats values
* Only show labels if train/dev mismatched
* Don't show label counts (only counting positive labels seems odd)
* Use warnings for mismatched train/dev labels
explosion/spaCy,honnibal/spaCy,explosion/spaCy,honnibal/spaCy,explosion/spaCy,honnibal/spaCy,honnibal/spaCy,explosion/spaCy,explosion/spaCy,explosion/spaCy