function inspectString(str, opts) {
    if (str.length > opts.maxStringLength) {
        var remaining = str.length - opts.maxStringLength;
        var trailer = '... ' + remaining + ' more character' + (remaining > 1 ? 's' : '');
        return inspectString($slice.call(str, 0, opts.maxStringLength), opts) + trailer;
    }
    // eslint-disable-next-line no-control-regex
    var s = $replace.call($replace.call(str, /(['\\])/g, '\\$1'), /[\x00-\x1f]/g, lowbyte);
    return wrapQuotes(s, 'single', opts);
}
Decode a RFC 5987 field value (gracefully).

@param {string} str
@return {string}
@private