Merge branch '6.x' into 8.x

Author: driesvints

src/Illuminate/Database/DetectsLostConnections.php

@@ -54,6 +54,7 @@ protected function causedByLostConnection(Throwable $e)
             'SQLSTATE[08S01]: Communication link failure',
             'SQLSTATE[08006] [7] could not connect to server: Connection refused Is the server running on host',
             'SQLSTATE[HY000]: General error: 7 SSL SYSCALL error: No route to host',
+            'The client was disconnected by the server because of inactivity. See wait_timeout and interactive_timeout for configuring this behavior.',
         ]);
     }
 }