patch 8.1.0889: MS-Windows: a channel write may hang

Problem:    MS-Windows: a channel write may hang.
Solution:   Check for WriteFile() not writing anything. (Yasuhiro Matsumoto,
            closes #3920)
diff --git a/src/version.c b/src/version.c
index e31b7ca..a990f2c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -784,6 +784,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    889,
+/**/
     888,
 /**/
     887,