patch 8.1.0986: rename() is not propertly tested

Problem:    rename() is not propertly tested.
Solution:   Add tests. (Dominique Pelle, closes #4061)
diff --git a/src/version.c b/src/version.c
index 9b87302..3132a1d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -780,6 +780,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    986,
+/**/
     985,
 /**/
     984,