extensions/configuration-editing/src/configurationEditingMain.ts/registerSettingsCompletions
function registerSettingsCompletions(): vscode.Disposable {
	return vscode.languages.registerCompletionItemProvider({ language: 'jsonc', pattern: '**/settings.json' }, {
		provideCompletionItems(document, position, token) {
			return new SettingsDocument(document).provideCompletionItems(position, token);
		}
	});
}