lib: add node: prefix in sys module deprecation warning

Author: dario-piotrowicz

lib/sys.js

@@ -27,5 +27,5 @@
 // Note to maintainers: Although this module has been deprecated for a while
 // we do not plan to remove it. See: https://github.com/nodejs/node/pull/35407#issuecomment-700693439
 module.exports = require('util');
-process.emitWarning('sys is deprecated. Use util instead.',
+process.emitWarning('sys is deprecated. Use `node:util` instead.',
                     'DeprecationWarning', 'DEP0025');