doc: indent child list items for remark-lint

Child items not aligned to parent are flagged by list-item-bullet-indent

PR-URL: https://github.com/nodejs/node/pull/29488


Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>