When an active todo.txt file is deleted (or becomes unavailable), the tab is closed, but the file's contents still show on the screen

[DeflateAwning]

Bug Report

Important

App Version: v2.0.12-rc.1

Platform: Linux

Installation Method: deb

Steps to Reproduce:
0. Ensure that you have at least one normal tab open in sleek.

1. Create an empty todo.txt file.
2. Fill it with a todo item.
3. Open that file with sleek, and have it active (i.e., that tab is active).
4. Delete the file on disk.
5. Observe that the tab is removed/deleted, but that the todo list still shows the previous todo items in that file from before it was deleted.

Expected behavior:
When the file is deleted, the tab should close (as it currently does), but the todo list should show the todo items in the file that becomes active.

Notes:
This doesn't seem like a big deal, but it comes up quite a bit with Syncthing because files become unwritable briefly sometimes.

In addition to fixing this bug, it'd be awesome if Sleek didn't require closing/reopening the file if it's resynced by Syncthing (but that's probably a bigger fix).

[ransome1]

@DeflateAwning could you please check if this now works as expected in the latest pre-release?

[DeflateAwning]

Haven't seen it break, but this one's a tough one to verify as it was only happening sometimes. Thanks for the fix; will update if I see it happen again!