doc,tools: remove `checkLinks.mjs`
The checks made by this are now integrated to remark-preset-lint-node, there are no reason to keep it around anymore.
Blocked on https://github.com/nodejs/node/pull/39201 (first commit is from there).
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
The checks made by this are now integrated to remark-preset-lint-node, there are no reason to keep it around anymore.
Blocked on https://github.com/nodejs/node/pull/39201 (first commit is from there).