Revert "Silence warning when requiring ruby-ts-mode"

This reverts commit bf817069.

We deliberately don't silence these warnings, so that a user who loads
the mode without having the grammar installed sees the warning and
realizes the problem in time to fix it.

lisp/progmodes/ruby-ts-mode.el

@@ -1206,7 +1206,7 @@ leading double colon is not added."
       (syntax-ppss-flush-cache (cl-loop for r in ranges
                                         minimize (car r))))))
 
-(if (treesit-ready-p 'ruby t)
+(if (treesit-ready-p 'ruby)
     ;; Copied from ruby-mode.el.
     (add-to-list 'auto-mode-alist
                  (cons (concat "\\(?:\\.\\(?:"