patch 9.0.1586: error for using two messages with ngettext() differing in "%"

Problem:    Checking translations gives an error for using two messages with
            ngettext() that differ in "%" items.
Solution:   Adjust the check script to tolerate omitting one "%" item.
diff --git a/src/version.c b/src/version.c
index 27e558a..fdb7716 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1586,
+/**/
     1585,
 /**/
     1584,