src/vs/platform/extensionManagement/node/extensionsScanner.ts/ExtensionsScanner/setUninstalled
class ExtensionsScanner:	async setUninstalled(...extensions: ILocalExtension[]): Promise<void> {
		const extensionKeys: ExtensionKey[] = extensions.map(e => ExtensionKey.create(e));
		await this.withUninstalledExtensions(uninstalled => {
			extensionKeys.forEach(extensionKey => uninstalled[extensionKey.toString()] = true);
		});
	}