Trying to grade a textbook should give the right reason why you can't

Description of your request or bug report:

(A very minor UI thing, but I figured I’d report it…)

Textbooks are deliberately set as an ungradeable category in Natively. However, the “Why can’t I grade this item?” link on a textbook’s page only gives you the generic

Can’t grade quite yet. .

Grading is only allowed on items you’ve finished or stopped. See here for more details on our grading system.

dialogue, even when you have marked the textbook as “finished”. Ideally the message for a book in an excluded-from-grading category should say “This item is in a category we’ve excluded from grading.”

PS: is it intentional that the ellipsis in the dialog box title has only two dots, not three?

Trello link: