doc: change lang info string in fs JS snippets

Refs: nodejs/remark-preset-lint-node#176

PR-URL: nodejs#37605
Refs: nodejs#37162
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Danielle Adams <[email protected]>
Reviewed-By: Darshan Sen <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>

Author: aduh95