patch 9.0.1856: issues with formatting positional arguments

Problem:  issues with formatting positional arguments
Solution: fix them, add tests and documentation

closes: #12140
closes: #12985

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Christ van Willegen <cvwillegen@gmail.com>
Tentatively fix message_test. Check NULL ptr.
diff --git a/src/version.c b/src/version.c
index a07a2bf..98964fb 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1856,
+/**/
     1855,
 /**/
     1854,