static indent(s) {
		if (Array.isArray(s)) {
			return s.map(Template.indent).join("\n");
		}
		const str = s.trimEnd();
		if (!str) return "";
		const ind = str[0] === "\n" ? "" : "\t";
		return ind + str.replace(/\n([^\n])/g, "\n\t$1");
	}
@param {string | string[]} s string to convert to identity
@returns {string} converted identity