patch 9.0.1051: after a failed CTRL-W ] next command splits window

Problem:    After a failed CTRL-W ] next command splits window.
Solution:   Reset postponed_split. (Rob Pilling, closes #11698)
diff --git a/src/version.c b/src/version.c
index f72d537..5248bcf 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1051,
+/**/
     1050,
 /**/
     1049,