fix imports

lib/util/rbtree_wrapper.js

@@ -1,7 +1,7 @@
 // Tiny wrapper around function-red-black-tree that overrides the [inspect.custom] symbol so when we print it (during debugging) we just see the (key=>value)-pairs instead of the tree structure.
 
 import createRBTree from "functional-red-black-tree";
-import { inspect } from "util";
+import { inspect } from "node:util";
 
 function defaultPrintf(depth, options, inspect) {
   const entries = [];