Add "show diff" when user closes not saved file

[Specyk]

When user closes not saved file there are 3 options in saving dialog:

• don't save
• cancel
• save

I think there is missing an extra option "Show diff" which shows the difference between last saved file and current version. Alternatively the difference could be displayed always when saving file dialog appears.

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Problems Saving Jupyter Notebook (#114588)
• Manually restoring modified file back to saved state requires save (#5783)
• Allow diff between current open file's changes and the saved original (#62378)
• error highlight (#123064)
• boosfail to save file i am trying to save file but it does nt work 3 options retry , save as , discard were show on screen when i click on save as vs code said ur index.html file already existtrap (#122105)

[vscode-triage-bot]

This feature request is now a candidate for our backlog. The community has 60 days to upvote the issue. If it receives 20 upvotes we will move it to our backlog. If not, we will close it. To learn more about how we handle feature requests, please see our documentation.

Happy Coding!

[vscode-triage-bot]

This feature request has not yet received the 20 community upvotes it takes to make to our backlog. 10 days to go. To learn more about how we handle feature requests, please see our documentation.

Happy Coding!

[MurzNN]

Similar issue #62378 is marked as duplicate of #26339 but I think this is wrong, current feature is more precise and much easier to implement.
P.S. Here also my duplicate of this issue: #128539

[vscode-triage-bot]

🙁 In the last 60 days, this feature request has received less than 20 community upvotes and we closed it. Still a big Thank You to you for taking the time to create this issue! To learn more about how we handle feature requests, please see our documentation.

Happy Coding!