repl: use _Node.js_ in user-facing REPL text

We use _node (REPL)_ in one place and _Node.js (REPL)_ in another place
in error messages in repl.js. Use _Node.js_ in both places.

PR-URL: https://github.com/nodejs/node/pull/34644


Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>