[Discussion] [Live Share] Restricting linting to local files

[lostintangent]

In preparation for Visual Studio Live Share adding support for "guests" to receive remote language services from a host, this PR simply updates the current DocumentSelector to be limited to file and untitled (unsaved) files. This way, when someone has the TSLint extension installed, and joins a Live Share session (where files use the vsls: scheme), their language services will be entirely derived from the remote/host side, which provides a more accurate and project-wide experience.

// CC @egamma

[egamma]

@lostintangent thanks for the PR.
Since, tslint doesn´t support untitled files. I´ve inlined the document selector defintion rather than using flatMap. This also doesn´t introduce a dependency on lodash.

		documentSelector: [
			{ language: 'typescript', scheme: 'file' },
			{ language: 'typescriptreact', scheme: 'file' },
			{ language: 'javascript', scheme: 'file' },
			{ language: 'javascriptreact', scheme: 'file' }
		],