node_t -> ast_node_t

Clearer to understand the intent of node_t as a direct result of
parsing source code.

obi.c

@@ -25,11 +25,11 @@ typedef struct
 #endif
 } machine_t;
 
-void interpret(machine_t *cpu, node_t *ast, size_t num)
+void interpret(machine_t *cpu, ast_node_t *ast, size_t num)
 {
   for (size_t i = 0; i < num; ++i)
   {
-    node_t node = ast[i];
+    ast_node_t node = ast[i];
     switch (node.type)
     {
     case NEXT: