patch 8.0.0839: cannot kill a job in a terminal with CTRL-C

Problem:    Cannot kill a job in a terminal with CTRL-C.
Solution:   Set the controlling tty and send SIGINT. (closes #1910)

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    839,
 /**/
     838,
 /**/