Don't produce non-ASCII characters in *scratch*

* lisp/startup.el (initial-scratch-message): Quote apostrophes to
avoid producing non-ASCII characters in the *scratch* buffer's
commentary.

lisp/startup.el

@@ -1430,9 +1430,9 @@ settings will be marked as \"CHANGED outside of Customize\"."
      (put 'cursor 'face-modified t))))

(defcustom initial-scratch-message (purecopy "\
;; This buffer is for notes you don't want to save, and for Lisp evaluation.
;; This buffer is for notes you don\\='t want to save, and for Lisp evaluation.
;; If you want to create a file, visit that file with \\[find-file],
;; then enter the text in that file's own buffer.
;; then enter the text in that file\\='s own buffer.

")
  "Initial documentation displayed in *scratch* buffer at startup.