fix(pgw): mention rdb not compatible with ssh bastion (#4776)

Author: RoRoJ

pages/public-gateways/how-to/use-ssh-bastion.mdx

@@ -168,4 +168,8 @@ Carry out the following steps to avoid the need to repeat `-J bastion@<public-IP
 2. Click the Public Gateway you want to deactivate SSH bastion on. You are taken to the **Overview** page for that Public Gateway.
 3. Under **SSH Bastion** use the toggle <Icon name="toggle"/> to deactivate the bastion.
 
-    SSH bastion is deactivated on this gateway. You can reactivate it at any time.
+    SSH bastion is deactivated on this gateway. You can reactivate it at any time.
+
+## SSH bastion limitations and troubleshooting
+
+Note that you cannot use Public Gateway SSH bastion to connect to resources such as Managed Databases, which are not compatible with SSH.