anchor.diff:  * `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).
  +Colors are defined using hexadecimal format (e.g., #ff0000 for red).
   
   Use the `Text` token to set the background color of the source block and the default text color.
   
  
positive.code: |font-style
  |<<font-styles,Font style>> +
  (default: normal)
  |iamge:
    alt:
      font-style: italic
  
  
negative.code: 
  The pseudo-HTML in Asciidoctor PDF evolved from the inline formatting in Prawn, now supporting the following elements: a, br, button, code, color, del, em, font, img, key, mark, span, strong, sub, sup.
  All decimal and hexadecimal character references are supported, as well as the named entities amp, apos, gt, lt, nbsp, and quot (e.g., `\&apos;`).
  You can change the font color using `rgb` attribute on the `color` element (e.g., `<color rgb="#ff0000">`) and the font family and size using `name` and `size` attributes on the `font` element, respectively (e.g., `<font name="sans" size="12">`).
  You can also use the `style` attribute on `span` to control the font color, weight, and style using the relevant CSS property names.
  The pseudo-HTML in Asciidoctor PDF also supports the `class` attribute on any element for applying roles from the theme.
  (Though not recommended, you can pass this pseudo-HTML straight through to Prawn using an inline passthrough in AsciiDoc).
  