chore(kubeadm): improve add-linux-nodes documentation

Signed-off-by: lekaf974 <[email protected]>

Author: lekaf974

content/en/docs/tasks/administer-cluster/kubeadm/adding-linux-nodes.md

@@ -68,6 +68,12 @@ The output is similar to this:
 5didvk.d09sbcov8ph2amjw
 ```
 
+To print a kubeadm join command while also generating a new token you can use:
+
+```bash
+sudo kubeadm token create --print-join-command
+```
+
 If you don't have the value of `--discovery-token-ca-cert-hash`, you can get it by running the
 following commands on the control plane node: