Enhancements to set-mark-command and exchange-point-and-mark.

etc/NEWS

@@ -329,6 +329,17 @@ each time, so you can mark the next two sexps with M-C-SPC M-C-SPC,
 for example.  This feature also works for mark-end-of-sentence, if you
 bind that to a key.
 
+** Repeating set-mark-command immediately, i.e. C-SPC C-SPC, will enable
+transient-mark-mode temporarily if not already enabled.
+
+** A prefix argument is no longer required to repeat a jump to a
+previous mark, i.e. C-u C-SPC C-SPC C-SPC ... will cycle through the
+mark ring.  Use C-u C-u C-SPC to set the mark immediately after a jump.
+
+** When the mark is active, and transient-mark-mode is not enabled,
+C-u C-x C-x (exchange-point-and-mark) will temporarily activate
+transient-mark-mode.
+
 ** In the *Occur* buffer, `o' switches to it in another window, and
 C-o displays the current line's occurrence in another window without
 switching to it.