(simple-diary-display, fancy-diary-display): Pass proper format string to message.

lisp/calendar/diary-lib.el

@@ -385,7 +385,7 @@ changing the variable `diary-include-string'."
             (and (not (cdr diary-entries-list))
                  (string-equal (car (cdr (car diary-entries-list))) "")))
         (if (<= (length msg) (frame-width))
-            (message msg)
+            (message "%s" msg)
           (set-buffer (get-buffer-create holiday-buffer))
           (setq buffer-read-only nil)
           (calendar-set-mode-line date-string)
@@ -422,7 +422,7 @@ This function is provided for optional use as the `diary-display-hook'."
                           (concat date-string (if holiday-list ":" ""))
                           (mapconcat 'identity holiday-list "; "))))
         (if (<= (length msg) (frame-width))
-            (message msg)
+            (message "%s" msg)
           (set-buffer (get-buffer-create holiday-buffer))
           (setq buffer-read-only nil)
           (calendar-set-mode-line date-string)