doc: improve module.builtinModules documentation

PR-URL: #17712
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: watson

doc/api/modules.md

@@ -841,11 +841,19 @@ added: v9.3.0
 A list of the names of all modules provided by Node.js. Can be used to verify
 if a module is maintained by a third-party module or not.
 
+Note that `module` in this context isn't the same object that's provided
+by the [module wrapper][]. To access it, require the `Module` module:
+
+```js
+const builtin = require('module').builtinModules;
+```
+
 [`__dirname`]: #modules_dirname
 [`__filename`]: #modules_filename
 [`Error`]: errors.html#errors_class_error
 [`module` object]: #modules_the_module_object
 [`path.dirname()`]: path.html#path_path_dirname_path
 [exports shortcut]: #modules_exports_shortcut
 [module resolution]: #modules_all_together
+[module wrapper]: #modules_the_module_wrapper
 [native addons]: addons.html