patch 9.0.0345: error message for list argument could be clearer

Problem:    Error message for list argument could be clearer.
Solution:   Include the argument number. (Yegappan Lakshmanan, closes #11027)
diff --git a/src/match.c b/src/match.c
index 335b060..ebdaeab 100644
--- a/src/match.c
+++ b/src/match.c
@@ -1087,11 +1087,8 @@
 		|| check_for_opt_number_arg(argvars, 1) == FAIL))
 	return;
 
-    if (argvars[0].v_type != VAR_LIST)
-    {
-	emsg(_(e_list_required));
+    if (check_for_list_arg(argvars, 0) == FAIL)
 	return;
-    }
     win = get_optional_window(argvars, 1);
     if (win == NULL)
 	return;