patch 8.2.0459: cannot check if a function name is correct

Problem:    Cannot check if a function name is correct.
Solution:   Add "?funcname" to exists().

src/version.c

@@ -738,6 +738,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    459,
 /**/
     458,
 /**/