GitHub task lists are represented in HTML as unordered lists with checkboxes. When turned into text the checkboxes are currently ignored. This affects PRs with task lists (e.g. git/git#1359); the resulting text list has no indication anymore whether an item was checked (done) or not.

E.g. this:

• done item
• item still to do

Is turned into:

* done item
* item still to do

Format checkboxes by representing checked ones by "[x]" and unchecked ones by "[ ]" to keep the information of which item was done.

This turns the text result for the example above into:

* [x] done item
* [ ] item still to do