patch 8.1.1869: code for the argument list is spread out

Problem:    Code for the argument list is spread out.
Solution:   Put argument list code in arglist.c. (Yegappan Lakshmanan,
            closes #4819)

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1869,
 /**/
     1868,
 /**/