[FEATURE REQUEST] click to check off or uncheck checklist items

To vote: link to UserVoice item

It would be useful to be able to check items off and to click them again to uncheck them:
image

* [ ] checklist item 1
* [ ] checklist item 2
* [x] checklist item 3
* [x] checklist item 4
* [ ] checklist item 5

Also making these checkboxes via an emoji such as: :white_check_mark: or :ballot_box_with_check: would be more clear.