* lisp/gnus/gnus-score.el (gnus-summary-increase-score): Rename
'char-to-type' variable to 'char-to-types' and bind all legal types
for date header.
* lisp/gnus/gnus-score.el (gnus-summary-score-entry): Provide better
default values for each scoring type and cast 'match' to number only
if necessary.
Co-authored-by: Alex Bochannek <alex@bochannek.com>