clarify that disconnect only works with WSMan (#2344)

Author: SteveL-MSFT

reference/6/Microsoft.PowerShell.Core/About/about_Remote_Disconnected_Sessions.md

@@ -21,7 +21,7 @@ continue to run while the session is disconnected.
 
 The Disconnected Sessions feature is available only when the computer at the
 remote end of a connection is running Windows PowerShell 3.0 or a later
-version of Windows PowerShell.
+version of Windows PowerShell and using the WSMan transport.
 
 The Disconnected Sessions feature allows you to close the session in which a
 PSSession was created, and even close Windows PowerShell, and shut down the

reference/6/Microsoft.PowerShell.Core/Disconnect-PSSession.md

@@ -45,6 +45,8 @@ The **Disconnect-PSSession** cmdlet disconnects a Windows PowerShell session (**
 As a result, the **PSSession** is in a disconnected state.
 You can connect to the disconnected **PSSession** from the current session or from another session on the local computer or a different computer.
 
+Note that this capability only works with PSSessions using the WSMan transport.
+
 The **Disconnect-PSSession** cmdlet disconnects only open **PSSessions** that are connected to the current session.
 **Disconnect-PSSession** cannot disconnect broken or closed **PSSession** objects, or interactive **PSSession** objects started by using the Enter-PSSession cmdlet, and it cannot disconnect **PSSession** objects that are connected to other sessions.