patch 8.0.0560: :windo allows for ! but it's not supported

Problem:    :windo allows for ! but it's not supported.
Solution:   Disallow passing !. (Hirohito Higashi)
diff --git a/src/version.c b/src/version.c
index e73e1fa..325be55 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    560,
+/**/
     559,
 /**/
     558,