anchor.diff:  * Passing an instance of the extension object.
   
   NOTE: In the first two cases, the lifecycle of the instance is managed by JRuby.
  -In the last case, the caller is the owner of the lifeycle of the object.
  +In the last case, the caller is the owner of the lifecycle of the object.
   
   TIP: Using an already created instance as an extension is useful when using CDI.
   For example, you can inject any extension inside the code and then register that instance as an extension.
  
positive.code: ----
  <1> Class must extend from `Treeprocessor`.
  <2> The `document` instance can be used to retrieve all blocks of the current document.
  <3> All of the selcect block's lines are retrieved.
  <4> To create a new block, you must use the `createBlock` method. Set the parent document, the context (_listing_), the text content, attributes and options.
  
  [source]
  
negative.code: 
  // What is the 'provided strategy', need a link
  
  NOTE: All the methods listed in Table 3 are overloaded to accommodate various input types and options.
  
  You retrieve an instance of the `Asciidoctor` interface from the factory method provided.
  
  