fixup doc link

Author: guybedford

doc/api/esm.md

@@ -1073,6 +1073,7 @@ success!
 [`import`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import
 [`module.createRequire()`]: modules.html#modules_module_createrequire_filename
 [`module.syncBuiltinESMExports()`]: modules.html#modules_module_syncbuiltinesmexports
+[package exports]: #esm_package_exports
 [dynamic instantiate hook]: #esm_dynamic_instantiate_hook
 [special scheme]: https://url.spec.whatwg.org/#special-scheme
 [the official standard format]: https://tc39.github.io/ecma262/#sec-modules