[Doc] add troubleshooting info for ray client (ray-project#36390)

https://ray-distributed.slack.com/archives/C01DLHZHRBJ/p1686672067902799

Cover the error message OSS user ran into.

doc/source/cluster/running-applications/job-submission/ray-client.rst

@@ -285,3 +285,10 @@ Uploads
 If a ``working_dir`` is specified in the runtime env, when running ``ray.init()`` the Ray client will upload the ``working_dir`` on the laptop to ``/tmp/ray/session_latest/runtime_resources/_ray_pkg_<hash of directory contents>``.
 
 Ray workers are started in the ``/tmp/ray/session_latest/runtime_resources/_ray_pkg_<hash of directory contents>`` directory on the cluster. This means that relative paths in the remote tasks and actors in the code will work on the laptop and on the cluster without any code changes. For example, if the ``working_dir`` on the laptop contains ``data.txt`` and ``run.py``, inside the remote task definitions in ``run.py`` one can just use the relative path ``"data.txt"``. Then ``python run.py`` will work on my laptop, and also on the cluster. As a side note, since relative paths can be used in the code, the absolute path is only useful for debugging purposes.
+
+Troubleshooting
+--------------
+
+Error: Attempted to reconnect a session that has already been cleaned up 
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+This error happens when Ray Client reconnects to a head node that does not recognize the client. This can happen if the head node restarts unexpectedly and loses state. On Kubernetes, this can happen if the head pod restarts after being evicted or crashing.