patch 9.0.0822: crash when dragging the statusline with a mapping

Problem:    Crash when dragging the statusline with a mapping.
Solution:   Check for valid window pointer. (issue #11427)
diff --git a/src/version.c b/src/version.c
index 58f17e1..387c811 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    822,
+/**/
     821,
 /**/
     820,