lang: ast: add stub functions for retrieving, printing, interating, and destroying ast nodes

lang/ast/node.c

@@ -78,3 +78,11 @@ enum ivy_status ast_node_add_child(
 
 	return add_child(parent, child);
 }
+
+void ivy_ast_node_print(struct ivy_ast_node *node)
+{
+}
+
+void ivy_ast_node_destroy(struct ivy_ast_node *node)
+{
+}