Deprecate the --unity-launch flag

[ThatOneCalculator]

Reup of #40986

--unity-launch appears in the Linux desktop file and is currently undocumented. The flags acts as an alias to --new-window, forcing a new window to be spawned when opening files.

refs:

vscode/src/vs/platform/launch/electron-main/launchMainService.ts

Lines 150 to 152 in c7ea84b

	if (args['new-window'] || args['unity-launch'] || baseConfig.forceProfile || baseConfig.forceTempProfile) {
	openNewWindow = true;
	}

vscode/src/vs/code/electron-main/app.ts

Line 1352 in c7ea84b

forceNewWindow: args['new-window'] || (!hasCliArgs && args['unity-launch']),

https://www.reddit.com/r/linuxquestions/comments/s4hvdv/comment/hsruzir/

[Tyriar]

It was added to make things work a little nicer under unity, I think specifically shift+click opening a new window (but it was a long time ago I added it). It's slightly different to --new-window and I suspect we don't probably don't need it anymore so I don't think we should document it. When we remove it'll need some verification to make sure there aren't any bad regressions.

[ThatOneCalculator]

Awesome, thanks for the clarification! Guessing the .desktop file will use --new-window then from now on since that's the desired behavior for most desktop environments nowadays

[Firestar-Reimu]

https://aur.archlinux.org/cgit/aur.git/tree/code.desktop?h=visual-studio-code-bin

the --unity-launch leads to tiny cursors on HiDPI settings.

See #136390 (comment)

The fastest fix is to delete the --unity-launch option, just /usr/bin/code is fine.