doc: revise TLS minVersion/maxVersion text

Minor changes mostly to improve compliance with our style guide.

PR-URL: https://github.com/nodejs/node/pull/38202


Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>