Breaking

• None.

Enhancements

• Allow custom_categories to specify a regex for a child.
  Enrico Zannini
  #688

• Update Javascript: KaTeX 0.16.25
  John Fairhurst

Bug Fixes

• Don't call extension members that do not need documentation
  'undocumented'.
  John Fairhurst

• Work around activesupport vs. concurrent-ruby crash.
  John Fairhurst
  #1414

• Better identify default implementations.
  John Fairhurst
  #1420

• Suppress warning on extensions providing default implementations.
  John Fairhurst
  #1396