anchor.diff:  One case where this is useful is when referencing the `page-number` attribute.
   If you unset the `pagenums` attribute on the document, any line in the running content that makes reference to `\{page-number}` will be dropped.
   
  -You can also built-in AsciiDoc text replacements like `+(C)+`, numeric character references like `+&#169;+`, hexidecimal character references like `+&#x20ac;+`, and inline formatting (e.g., bold, italic, monospace).
  +You can also built-in AsciiDoc text replacements like `+(C)+`, numeric character references like `+&#169;+`, hexadecimal character references like `+&#x20ac;+`, and inline formatting (e.g., bold, italic, monospace).
   
   Here's an example that shows how attributes and replacements can be used in the running footer:
   
  
positive.code: * `inline_block` - fill the background color to the height of the line (Asciidoctor PDF only)
  * `extend` - extend the background color to the end of the line for a line-oriented match (Asciidoctor PDF only)
  
  Colors are defined using hexidecimal format (e.g., #ff0000 for red).
  
  Use the `Text` token to set the background color of the source block and the default text color.
  
  
negative.code: ----
  
  As it stands, the converter doesn't do anything differently than the primary converter because we haven't yet overridden any of its methods.
  Let's do that now, starting by overriding the thematic break (aka horizontal rule) to make it render like a ribbon:
  
  [source,ruby]
  ----
  