Add an option to quicky save the file in discard changes dialog

[MarcAnt01]

[prayaas-a]

Good idea. I think the behavior should align more closely with the Win32 Notepad as that's the expected behavior for most users of this app. A prompt that has the options "Save", "Don't Save" or "Discard", as well as "Cancel." It's better to have a nondestructive action as the first ("Yes") option which is the opposite of how it is currently.