patch 8.0.1799: no test for :registers command

Problem:    No test for :registers command.
Solution:   Add a test. (Dominique Pelle, closes #2880)
diff --git a/src/version.c b/src/version.c
index 0f0a1b7..7f7e1b6 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1799,
+/**/
     1798,
 /**/
     1797,