Fix S-<return> and M-S-<return> keybindings for GUI

This prevents these key combinations from being translated to M-RET in
window systems. These bindings already have extra keys defined for
TTY.

lisp/org.el

@@ -18859,9 +18859,9 @@ COMMANDS is a list of alternating OLDDEF NEWDEF command names."
 (define-key org-mode-map (kbd "<backtab>") #'org-shifttab)
 
 ;;;; RET key with modifiers
-(org-defkey org-mode-map (kbd "S-RET") #'org-table-copy-down)
-(org-defkey org-mode-map (kbd "M-S-RET") #'org-insert-todo-heading)
-(org-defkey org-mode-map (kbd "ESC S-RET") #'org-insert-todo-heading)
+(org-defkey org-mode-map (kbd "S-<return>") #'org-table-copy-down)
+(org-defkey org-mode-map (kbd "M-S-<return>") #'org-insert-todo-heading)
+(org-defkey org-mode-map (kbd "ESC S-<return>") #'org-insert-todo-heading)
 (org-defkey org-mode-map (kbd "M-RET") #'org-meta-return)
 (org-defkey org-mode-map (kbd "ESC RET") #'org-meta-return)