[S-mailx] oauth timeout

[Stephen Isard]

It turns out that using on-main-loop-tick to check whether it is time to 
renew the auth token doesn't cover the case where you spend a long time 
writing a message in the external editor.  You come back from the editor 
to find that imap has timed out and there is no open folder.

Since I have defined an account for logging in with oauth, I should be 
able to give the command
account oauth
to reconnect.  However, I find that I have to issue the command twice. 
The first time, I just get a message that there is no open folder.

Is there some way of trapping the imap disconnection error to trigger a 
new 'account oauth'?  I see code snippets involving 'trap' in the man 
page, but no entry for it in the list of commands.

Stephen Isard