doc: remove space above version picker

PR-URL: https://github.com/nodejs/node/pull/34768
Fixes: https://github.com/nodejs/node/issues/34767
Fixes: https://github.com/nodejs/node/issues/34447


Reviewed-By: Derek Lewis <DerekNonGeneric@inf.is>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Harshitha K P <harshitha014@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>