docs: use gh alert syntax for callouts

Signed-off-by: David Karlsson <35727626+dvdksn@users.noreply.github.com>

docs/reference/commandline/node_update.md

@@ -19,8 +19,7 @@ Update a node
 
 Update metadata about a node, such as its availability, labels, or roles.
 
-> **Note**
->
+> [!NOTE]
 > This is a cluster management command, and must be executed on a swarm
 > manager node. To learn about managers and workers, refer to the
 > [Swarm mode section](https://docs.docker.com/engine/swarm/) in the