Tutorial Part2: Give the player a canche to undo his move

in case he started an attack from the water. The warning
makes no sense otherwise.

[ci skip]

(cherry picked from commit 9cac36e6b858cc9344674f5c90aa872e12e5ba9d)

data/campaigns/tutorial/scenarios/02_Tutorial_part_2.cfg

@@ -619,6 +619,9 @@ A full list of abilities and weapons specials, along with traits, may be found i
         [/message]
 
         {UNDO_REMINDER}
+
+        # cancel an eventually started attack to still allow undoing after the warning
+        [cancel_action][/cancel_action]
     [/event]
 
     # Remind them to keep back