✨ Deleting an open file externally should be indicated on open editor tabs

[austincondiff]

Description

If the file is deleted externally, in Finder for example, the file is left open and the tab should indicate that the reference is broken. When saved with ⌘S, it should be saved back to it's original location where the tab was pointing to.

[pro100filipp]

Hi, wanna try to work in this

[austincondiff]

Closing because of #1999.