~/.taggedmail-to-workflowy.rc should contain the GUID of a shared Workflowy node.
This sharing system is now obsolete and you can't make links like that any more
so uh this code should probably be updated.

Reads the mutt mailbox in $MAIL and looks for messages with X-Status headers
with an 'F' in them.  Those are messages that are 'flagged' in mutt.

Updates the Workflowy with the number, sender, and subject of those flagged
messages, deleting things from the Workflowy that don't correspond to tagged
messages in that format.