function toString (param) {
  if (!Array.isArray(param)) {
    const { from, to } = param
    return `[${from}-${to}]`
  }
  return `[${param.map(toString).join(', ')}]`
}
Converts a selection or an array of selections to a human-readable string
@param {{from: number, to: number} | Array<{from: number, to: number}>} param
@returns {string}