Fix description indentation

[chasecaleb]

Indent every line of description text so that asterisk-style bullet points won't be mistaken for org headings.

---

Example

Screenshot of task from Todoist website:

Original behavior:

*** Example
    :PROPERTIES:
    :TODOIST_ID: <redacted>
    :TODOIST_PROJECT_ID: <redacted>
    :END:

    * bullet point in description
* another

With this PR:

*** Example
    :PROPERTIES:
    :TODOIST_ID: 5175619419
    :TODOIST_PROJECT_ID: 2161829187
    :END:
   * bullet point in description
   * another

[abrochard]

Thank you!