doc: drop <b> of v20 changelog
See: https://github.com/nodejs/node-core-utils/pull/712#discussion_r1251338897
cc: @richardlau
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
See: https://github.com/nodejs/node-core-utils/pull/712#discussion_r1251338897
cc: @richardlau