Enable definition lists

[ehuss]

Problem

Currently there is no way to make a definition list without using HTML. These can be a useful semantic and presentation structure.

Proposed Solution

After updating to pulldown-cmark 0.13, enable the ENABLE_DEFINITION_LIST option. Definition lists look like:

title 1
  : definition 1
title 2
  : definition 2

The spec is at: https://github.com/pulldown-cmark/pulldown-cmark/blob/master/pulldown-cmark/specs/definition_lists.txt

Notes

No response