Add extra note about deleting .csync_journal.db

This is added as per the recommendation from @guruz in #5252.

doc/troubleshooting.rst

@@ -54,7 +54,17 @@ Identifying Basic Functionality Problems
 "CSync unknown error"
 ---------------------
 
-If you see this error message stop your client, delete the ``.csync_journal.db`` file, and then restart your client. There is a  ``.csync_journal.db`` file inside the folder of every account configured on your client. See https://github.com/owncloud/client/issues/5226 for more discussion of this issue.
+If you see this error message stop your client, delete the
+``.csync_journal.db`` file, and then restart your client. 
+There is a  ``.csync_journal.db`` file inside the folder of every account
+configured on your client. 
+
+.. NOTE::
+   Please note that this will also erase some of your settings about which
+   files to download.
+   
+See https://github.com/owncloud/client/issues/5226 for more discussion of this
+issue.
 
 
 Isolating other issues