docs: add warnings about backing up keyring to snapshot commands (#19400

)

The `operator snapshot` commands and agent don't back up Nomad's key
material. Add some warnings about this to places where users might be looking
for information on cluster recovery.

Fixes: #19389

website/content/docs/commands/operator/snapshot/agent.mdx

@@ -19,6 +19,15 @@ automatic failover. In daemon mode, the agent will also register itself with
 Consul as a service, along with health checks that show the agent is alive
 and able to take snapshots.
 
+<Warning>
+
+This snapshot agent only saves a Raft snapshot. Key material for the Nomad
+keyring is stored on disk and must be saved separately. To use a snapshot saved
+by the agent to recover a cluster, you will also need to [restore the keyring][]
+onto at least one server.
+
+</Warning>
+
 If ACLs are enabled, a management token must be supplied in order to perform
 snapshot operations.
 
@@ -155,3 +164,5 @@ Note that despite the AWS references, any S3-compatible endpoint can be specifie
 ### Google Storage Options
 
 - `-google-bucket`: The bucket to use.
+
+[restore the keyring]: /nomad/docs/operations/key-management#restoring-the-keyring-from-backup

website/content/docs/commands/operator/snapshot/save.mdx

@@ -14,6 +14,13 @@ recovery].
 If ACLs are enabled, a management token must be supplied in order to perform
 snapshot operations.
 
+<Warning>
+
+This command only saves a Raft snapshot. If you use this snapshot to recover a
+cluster, you will also need to [restore the keyring][] onto at least one server.
+
+</Warning>
+
 To create a snapshot from the leader server and save it to "backup.snap":
 
 ```shell-session
@@ -27,10 +34,6 @@ leader is available):
 $ nomad operator snapshot save -stale backup.snap
 ```
 
-This command only saves a Raft snapshot. If you use this snapshot to recover a
-cluster, you will also need to [restore the keyring][] onto at least one server.
-
-
 ## Usage
 
 ```plaintext
@@ -49,4 +52,4 @@ nomad operator snapshot save [options] <file>
   server.
 
 [outage recovery]: /nomad/tutorials/manage-clusters/outage-recovery
-[restore the keyring]: /nomad/docs/operations/key-management#restoring-the-keyring-from-backu
+[restore the keyring]: /nomad/docs/operations/key-management#restoring-the-keyring-from-backup