patch 8.1.1439: json_encode() is very slow for large results

Problem:    Json_encode() is very slow for large results.
Solution:   In the growarray use a growth of at least 50%. (Ken Takata,
            closes #4461)

src/version.c

@@ -767,6 +767,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1439,
 /**/
     1438,
 /**/