patch 8.1.0899: no need to check restricted mode for setwinvar()

Problem:    No need to check restricted mode for setwinvar().
Solution:   Remove check_restricted().
diff --git a/src/version.c b/src/version.c
index a2c250e..f3e1081 100644
--- a/src/version.c
+++ b/src/version.c
@@ -784,6 +784,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    899,
+/**/
     898,
 /**/
     897,