patch 9.0.1599: Cursor not adjusted when 'splitkeep' is not "cursor"

Problem:    Cursor not adjusted when near top or bottom of window and
            'splitkeep' is not "cursor".
Solution:   Move boundary checks to outer cursor move functions, inner
            functions should only return valid cursor positions. (Luuk van
            Baal, closes #12480)
diff --git a/src/version.c b/src/version.c
index 320add5..872587e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1599,
+/**/
     1598,
 /**/
     1597,