patch 8.2.0860: cannot use CTRL-A and CTRL-X on unsigned numbers

Problem:    Cannot use CTRL-A and CTRL-X on unsigned numbers.
Solution:   Add "unsigned" to 'nrformats'. (Naruhiko Nishino, closes #6144)
diff --git a/src/version.c b/src/version.c
index 88f6da8..f63cb0c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    860,
+/**/
     859,
 /**/
     858,