anchor.diff:  * normalize space characters in authors content and drop lines with unresolved attribute references (#1642)
   * skip image block with missing image if computed alt text resolves to empty string (#1645)
   * custom theme does not inherit from base theme by default; must be specified explicitly using `extends: base` (#1640)
  -* allow theme to confiure number of index columns using `index_columns` key (#1663)
  +* allow theme to configure number of index columns using `index_columns` key (#1663)
   * configure AsciiDoc table cell to inherit font properties from table and scale font size of nested blocks (#926)
   * scale font size of literal table cell (#1696)
   * add support for id attribute on link macro
  
positive.code: 
  Bug Fixes::
  
  * do not crash if item in horizontal desciption list has no desc
  * do not crash if item in unordered desciption list has no desc and do not append subject stop to term
  * resolve images in theme correctly when theme is loaded from classloader (JRuby only) (#1829)
  * log warning rather than crash if front cover image cannot be embedded (such as a broken SVG)
  * do not hyphenate a hyphen when hyphenation is enabled (#1562)
  
negative.code: 
  == 1.5.0.rc.2 (2020-01-09) - @mojavelinux
  
  * patch Prawn to fix incompatibility with Ruby 2.7 (to fix text wrapping)
  * fix crash when assigning font style to header cell in table body (#1468)
  * fix parsing of array value of pdf-page-margin attribute (#1475)
  * fix warning when reading data from a remote URL when running with Ruby 2.7 (#1477)
  