Save changes dialog not working on close window / Alt-F4

[wdonders]

First: Love this Notepad! THE greatest annoyance of Windows 11 solved! :-)

The Issue:
When you have unsaved changes, and you exit the application with 'File' -> 'Exit' then a 'Save changes?' dialog pops up, which is great.
However, if you close the application by clicking on the 'X' on the top right of the window or by typing Alt-F4, the application closes without this dialog, which is not what you want.

(tested on Windows 10 and Windows 11)

[Tronco2018]

I think the code doesn't account for the WM_CLOSE and only for the WM_COMMAND so that's probably why. I would send a patch but I don't currently have windows so I can't compile the code.

[Tronco2018]

#15 issue is already discussing this