Markdown filter: Unchecked check-box is not extracted properly.

Created by: deeagraw

This is extension of the bug #687

The tasklist is defined as follows

- [x] Set up Jersey Shore recording
- [x] Buy donuts with sprinkles
- [x] Take nap
- [ ] Wash ferret

While extracting and merging, the unchecked task ("Wash ferret" here) is not rendered properly

The space is missing within the square brackets causing the issue.