update types for register.initialized

Author: danielpza

types/index.d.ts

@@ -1,5 +1,6 @@
 import TSNode from "ts-node";
 import ts from "typescript";
+import type { REGISTER_INSTANCE } from "ts-node";
 
 /* ****************************************************************************************************************** *
  * Hardcoded declarations file for npm package
@@ -22,6 +23,14 @@ export interface TransformerExtras {
 
 export function register(): TSNode.RegisterOptions | undefined;
 
+export declare namespace register {
+  function initialize(): {
+    tsNode: typeof TSNode;
+    instanceSymbol: typeof REGISTER_INSTANCE;
+    tsNodeInstance: TSNode.Service;
+  };
+}
+
 export default function transformer(
   program?: ts.Program,
   pluginConfig?: TsTransformPathsConfig,