add '.vscode' to .gitignore (#4594)

[Jongkeun]

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fixed #4594

When I saved some files, it was changed automatically due to vscode setting.
vscode default setting value of typescript.format.insertSpaceAfterFunctionKeywordForAnonymousFunctions is true
And I use this setting value all of my workspaces.

But it seems like svelte project is using false.
I want to try to join this project, but I couldn't change default settings for only this project.
Because my other projects are using true.
So I set some setting values and don't want to commit, because other people don't need this value.

I thought I would commit my .vscode/settings.json, but you might not want it.
So I commit only .gitignore 😃

[Jongkeun]

It was passed at my pc.
Should I something to do?😅

[Conduitry]

This makes sense. I also have a project-local .vscode/settings.json that overrides a couple of things, and I added it to .git/info/exclude, but having it in the shared .gitignore is probably more user friendly.