Automatically remove editors for deleted files

[msujew]

Motivation

Closes #648

Change description

Listens to any changes of open editors and removes them if the type indicates that the underlying file has been deleted.

Reviewer checklist

• PR addresses a single concern.
• The PR has no duplicates (please search among the Pull Requests before creating one)
• PR title and description are properly filled.
• Docs have been added / updated (for bug fixes / features)

[AlbyIanna]

LGTM

[per1234]

Tested on Windows and Linux and this fixes #648 for me in the following cases:

• Saved sketch
• New sketch
• Pulling to remote sketchbook after file deletion on Arduino Cloud

However, I did encounter a problem with unsaved sketches.

I don't know whether this would be considered in scope for this PR, or if it is more that this PR is only allowing us to reach a bug that has always existed, which should be fixed separately.

1. Select File > Preferences... from the Arduino IDE menus.
2. Uncheck the box next to "🗹 Auto save".
3. Click the OK button.
4. Click the downward pointing triangle button on the right side of the editor toolbar.
5. Select "New Tab" from the menu.
6. In the "Name for new file" field, type foo.
7. Click the OK button.
   The sketch will now contain a "foo.ino" tab.
8. Add some text to the "foo.ino" editor to make it "dirty".
   (added tab is saved even with auto save off, but that is an unrelated bug)
9. Click the downward pointing triangle button on the right side of the tab bar.
10. Select "Delete" from the menu.
11. Click the OK button on the "Move File to Trash" dialog.

🐛 I am presented with this perplexing dialog:

• Don't save - file is deleted, tab is removed from editor
• Cancel/X icon - file is deleted, tab is left in the editor with the "(deleted)" state
• Save - file is preserved, 🙁 tab is removed from the editor

Since the user has already been asked for confirmation about the deletion in the "Move File to Trash" dialog, I don't see any value in this additional "Do you want to save the changes you made to foo.ino (deleted)?" dialog.

[AlbyIanna]

I think this might be related to #893. Probably solving it in that PR will make this one work properly too.

Let's wait for #893 to be merged before doing anything here.

[msujew]

@AlbyIanna You're right, I will address this issue in #893 probably 👍

[msujew]

@per1234 Since #893 might take a while to get finished, I updated this PR to fix the issue you noticed. I found a clean solution. Please take another look :)

[per1234]

The problem I reported in my previous review no longer occurs and it also solves #648 as before.

Thanks @msujew!

[AlbyIanna]

LGTM! 🚀