function unexpectedBeforeAndAfter(keyword) {
	return [
		{ messageId: "unexpectedBefore", data: { value: keyword } },
		{ messageId: "unexpectedAfter", data: { value: keyword } },
	];
}
Gets error messages that unexpected space(s) before and after a specified
keyword.
@param {string} keyword A keyword.
@returns {string[]} Error messages.