Add new notable event type for log message `server drained and shutdown completed`

**Is your feature request related to a problem? Please describe.**
The [notable event types](https://www.cockroachlabs.com/docs/stable/eventlog.html) doc is auto-generated from https://github.com/cockroachdb/cockroach/blob/master/docs/generated/eventlog.md

Currently, CRDB contains a log message `server drained and shutdown completed` when a user [drains and shuts down a node](https://www.cockroachlabs.com/docs/v22.2/node-shutdown#stop-and-restart-a-node). However there isn't a corresponding notable event type for this event. While CRDB already contains notable event types like `node_decommissioned`, `node_decommissioning,` etc. there isn't a corresponding one for the `server drained and shutdown completed` log message.

**Describe the solution you'd like**
We include a new notable event type for that log message, perhaps with appropriate naming (tbd) like: `node_shutdown` or `node_drained` etc

**Additional context**
This came up in an internal [conversation](https://cockroachlabs.slack.com/archives/CHVV403F0/p1685628186733169) (link only accessible by Cockroach Labs internally)

Jira issue: CRDB-28432