patch 8.2.3849: functions implementing reduce and map are too long

Problem:    Functions implementing reduce and map are too long.
Solution:   Use a function for each type of value.  Add a few more test cases
            and add to the help. (Yegappan Lakshmanan, closes #9370)

src/version.c

@@ -749,6 +749,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3849,
 /**/
     3848,
 /**/