anchor.diff:   * ascending order this way:
    *
    *     Colors: <ul>
  - *       <li ng-repeat='color in colors | orderBy:""'>{{color}}</li>
  + *       <li ng-repeat="color in colors | orderBy:''">{{color}}</li>
    *     </ul>
    *
    * That would result in:
  
positive.code:  *       <li>red</li>
   *     <ul>
   *
   * The empty string expression, `""`, here signifies sorting in ascending order
   * using the default comparator.  Using `"+"` would also work as the `+` prefix
   * is implied.
   *
   * To sort in descending order, you would use the `"-"` prefix.
   *
   *     Colors: <ul>
   *       <li ng-repeat='color in colors | orderBy:"-"'>{{color}}</li>
   *     </ul>
   *
   * For this simple example, you could have also provided `true` as the addition
  
negative.code:  * then by first name when the last names are equal.  You would do that like
   * this:
   *
   *     <li ng-repeat="author in authors | orderBy:['lastName', 'firstName']">
   *
   * The items in such a list may either be string expressions or callables.  The
   * list itself might be provided as an expression that is looked up on the scope
  