anchor.diff:   *
    * If you want to list the authors sorted by `lastName`, you would use
    *
  - *     <li ng-repeat='author in authors | orderBy:"lastName"'>
  + *     <li ng-repeat="author in authors | orderBy:'lastName'">
    *       {{author.lastName}}, {{author.firstName
    *     </li>
    *
  - * The string expression, `"lastName"`, indicates that the sort should be on the
  + * The string expression, `'lastName'`, indicates that the sort should be on the
    * `lastName` property of each item.
    *
    * Using the lesson from the previous example, you may sort in reverse order of
    * lastName using either of the two methods.
    *
    *     <!-- reverse order of last names -->
  - *     <li ng-repeat='author in authors | orderBy:"-lastName"'>
  + *     <li ng-repeat="author in authors | orderBy:'-lastName'">
    *     <!-- also does the same thing -->
  - *     <li ng-repeat='author in authors | orderBy:"lastName":true'>
  + *     <li ng-repeat="author in authors | orderBy:'lastName':true">
    *
    * Note that, while we only discussed string expressions, such as `"lastName"`
    * or the empty string, you can also directly provide a custom callable that
    * will be called to transform the element before a sort.
    *
  - *     <li ng-repeat='author in authors | orderBy:getAuthorId'>
  + *     <li ng-repeat="author in authors | orderBy:getAuthorId">
    *
    * In the previous snippet, `getAuthorId` would evaluate to a callable when
    * evaluated on the [Scope] of the `<li>` element.  That callable is called once
  
positive.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
  
negative.code:  * ascending order this way:
   *
   *     Colors: <ul>
   *       <li ng-repeat="color in colors | orderBy:''">{{color}}</li>
   *     </ul>
   *
   * That would result in:
  