src/vs/platform/dialogs/common/dialogs.ts/getFileNamesMessage
export function getFileNamesMessage(fileNamesOrResources: readonly (string | URI)[]): string {
	const message: string[] = [];
	message.push(...fileNamesOrResources.slice(0, MAX_CONFIRM_FILES).map(fileNameOrResource => typeof fileNameOrResource === 'string' ? fileNameOrResource : basename(fileNameOrResource)));

	if (fileNamesOrResources.length > MAX_CONFIRM_FILES) {
		if (fileNamesOrResources.length - MAX_CONFIRM_FILES === 1) {
			message.push(localize('moreFile', "...1 additional file not shown"));
		} else {
			message.push(localize('moreFiles', "...{0} additional files not shown", fileNamesOrResources.length - MAX_CONFIRM_FILES));
		}
	}

	message.push('');
	return message.join('\n');
}