bug#60587: Patch for adding links to symbols' help documentation

[Gregory Heytings]

> > No, not any longer 😊.
>
> Can someone tell me an easy way to make that particular diamond 
> character display as the ASCII sequence `;-)'?

(defun set-character-display (char repl)
  (let ((c (char-from-name char)))
    (when (and c (stringp repl))
      (aset (or standard-display-table
                (setq standard-display-table (make-display-table)))
            c
            (vconcat
             (mapcar
              (lambda (char) (make-glyph-code char 'homoglyph))
              repl))))))

(set-character-display "SMILING FACE WITH SMILING EYES" ":-)")