-- in a task description gets excluded

**Describe the bug**
A clear and concise description of what the bug is.

Two `-`s in a row get filtered out of the final output.

**To Reproduce**
Steps to reproduce the behavior.

**Expected behavior**
A clear and concise description of what you expected to happen.

Two dashes should have been present between "Any" and "Thing"

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Technical Info (please complete the following information)**
- OS: MacOS
- Node.js Version: v10.6.0
- Taskbook Version: 0.1.1

Start by reproducing the task-description output described in the issue with Taskbook 0.1.1 on Node.js v10.6.0, using the attached screenshots as a reference. Trace how consecutive dashes are processed, and consider the issue done when two dashes between “Any” and “Thing” remain in the final output.

Written by the indexing model from the issue text.