calcurse: enable automatic note garbage collection

Removes note files no longer linked to any item on each save, instead of running calcurse -g by hand.

.config/calcurse/conf

@@ -20,7 +20,7 @@ format.notifytime=%T
 format.appointmenttime=%H:%M
 format.outputdate=%F
 format.dayheading=%B %e, %Y
-general.autogc=no
+general.autogc=yes
 general.autosave=yes
 general.confirmdelete=yes
 general.confirmquit=yes