tools: update alternative docs versions

Add `11.x` and mark `10.x` as `lts`.

PR-URL: https://github.com/nodejs/node/pull/23980


Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>