patch 8.0.1706: cannot sent CTRL-\ to a terminal window

Problem:    Cannot sent CTRL-\ to a terminal window.
Solution:   Make CTRL-W CTRL-\ send CTRL-\ to a terminal window.
diff --git a/src/version.c b/src/version.c
index 6c3b38d..4cba818 100644
--- a/src/version.c
+++ b/src/version.c
@@ -763,6 +763,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1706,
+/**/
     1705,
 /**/
     1704,