Clarify X2Go username.

content/anvil/connecting_to_linux_instances_using_x2go.md

@@ -39,7 +39,7 @@ Steps:
 Create a new session with the following settings:
 
 1.  Host: IP address of your instance
-2.  Login: centos
+2.  Login: Depends on the Linux version (For example: CentOS - `centos`, Alma - `almalinux`, Ubuntu - `ubuntu`, Fedora - `fedora`, etc.)  See the "Username to Connect" column on [this page]({{< relref "available_images" >}}) for a complete list.  Here `centos` is used.
 3.  RSA key: Configure with the id\_rsa key pair you used to create the
     instance
 4.  Session type: XFCE