patch 8.2.4609: :unhide does not check for failing to close a window

Problem:    :unhide does not check for failing to close a window.
Solution:   When closing a window fails continue with the next one.  Do not
            try closing the autocmd window. (closes #9984)
diff --git a/src/version.c b/src/version.c
index 2180ebf..cd3d9cd 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4609,
+/**/
     4608,
 /**/
     4607,