patch 8.1.0865: when 'listchars' only contains "nbsp:X" it does not work

Problem:    When 'listchars' only contains "nbsp:X" it does not work.
Solution:   Set extra_check when lcs_nbsp is set. (Ralf Schandl, closes #3889)
diff --git a/src/version.c b/src/version.c
index 7a02fbd..1bedce1 100644
--- a/src/version.c
+++ b/src/version.c
@@ -784,6 +784,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    865,
+/**/
     864,
 /**/
     863,