fix: Import URL and URLSearchParams in typings (#761)

This change adds an explicit import for the URL and URLSearchParams typings from the Node standard library `'url'` module.

This was needed to prevent the TypeScript compiler from issuing errors when compiling against targets where URL and URLSearchParams are not ambiently available.

Co-authored-by: Antoni Kepinski <xxczaki@pm.me>

index.d.ts

@@ -9,6 +9,7 @@
 
 /// <reference types="node" />
 
+import { URL, URLSearchParams } from 'url';
 import { Agent } from 'http';
 import { AbortSignal } from './externals';